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PubMed1999

Delayed interval delivery in multiple pregnancies. Is optimism justified?

OBJECTIVE: Evaluation of the success of delayed interval delivery in multiple pregnancies. METHOD: Retrospective analyses of all multiple pregnancies with the birth of one child at a gestational age of 16-31 weeks (n=80). Three groups were defined: group I, unsuccessful attempt to temporize delivery, group II, interval between the first child and the other child or children 3 hours or more, with delivery of the remaining children before 28 weeks and group III, prolongation of pregnancy beyond 28 weeks. RESULTS: In 15 multiple pregnancies (ten sets of twins, five sets of triplets), the aim was to postpone the delivery of the second (and third) child. The mean gestational age at admittance was 25 weeks. Delay of the delivery of the second child was achieved in ten cases, five in group II and five in group III. In groups II and III, the mean interval of delivery was 12 days; the gestational age at the delivery of the remaining children in these ten patients was 27 5/7 weeks. No relation could be found between the reason for admittance and the interval in delivery between the first and the other children. The only severe maternal complication was blood loss exceeding 2 liters. In the neonatal outcome of first and second children (with a gestational age of 28 weeks or more) no striking differences were observed. CONCLUSION: Delayed delivery in multiple pregnancies after the birth of the first child is only successful in a minority of patients and should be considered prior to the birth of the first child.

Birth Intervals↗

PubMed2001

Does the increased risk of preterm delivery in teenagers persist in pregnancies after the teenage period?

OBJECTIVE: To study the associations between low maternal age at first birth and the risks of very and moderately preterm birth, in first birth and in second successive birth in adulthood. DESIGN: Population-based cohort study. SETTING: Sweden. POPULATION Women aged less than 25 years at first birth (n = 275,933), having two successive live single births from 1973 through 1993. METHODS: Odds ratios with 95 percent confidence intervals were calculated to estimate the effect of low maternal age at first birth. Analyses of first births were adjusted for year of first birth and maternal education and in second births also for previous pregnancy outcomes and interpregnancy interval. MAIN OUTCOME MEASURES: Very preterm birth (less than 33 completed weeks) and moderately preterm birth (33-36 completed weeks). RESULTS: Compared with women aged 20 to 24 years at first birth, mothers aged 13 to 15 years were at increased risk of very preterm birth (odds ratio = 4.8). The corresponding risks among women aged 16 to 17 years at first birth were doubled (odds ratio = 2.3). The influence of maternal age on risks of moderately preterm birth was similar, although the age-related risks were lower. At second birth, risks of preterm birth were reduced in all age groups. However, mothers who were 17 years or less at first birth, faced, compared with mothers aged 20-24 years, significantly larger reduction in risks of very and moderately preterm birth. CONCLUSIONS: Our results suggest that there may be a biological effect of very young maternal age, affecting foremost very preterm birth.

Adolescent↗

PubMed2002

The interval between pregnancies and the risk of preeclampsia.

BACKGROUND: The risk of preeclampsia is generally lower in second pregnancies than in first pregnancies, but not if the mother has a new partner for the second pregnancy. One explanation is that the risk is reduced with repeated maternal exposure and adaptation to specific antigens from the same partner. However, the difference in risk might instead be explained by the interval between births. A longer interbirth interval may be associated with both a change of partner and a higher risk of preeclampsia. METHODS: We used data from the Medical Birth Registry of Norway, a population-based registry that includes births that occurred between 1967 and 1998. We studied 551,478 women who had two or more singleton deliveries and 209,423 women who had three or more singleton deliveries. RESULTS: Preeclampsia occurred during 3.9 percent of first pregnancies, 1.7 percent of second pregnancies, and 1.8 percent of third pregnancies when the woman had the same partner. The risk in a second or third pregnancy was directly related to the time that had elapsed since the preceding delivery, and when the interbirth interval was 10 years or more, the risk approximated that among nulliparous women. After adjustment for the presence or absence of a change of partner, maternal age, and year of delivery, the odds ratio for preeclampsia for each one-year increase in the interbirth interval was 1.12 (95 percent confidence interval, 1.11 to 1.13). In unadjusted analyses, a pregnancy involving a new partner was associated with higher risk of preeclampsia, but after adjustment for the interbirth interval, the risk of preeclampsia was reduced (odds ratio for preeclampsia with a change of partner, 0.73; 95 percent confidence interval, 0.66 to 0.81). CONCLUSIONS: The protective effect of previous pregnancy against preeclampsia is transient. After adjustment for the interval between births, a change of partner is not associated with an increased risk of preeclampsia.

Female↗

PubMed2000

Relationships between fatty liver and fertility and some periparturient diseases in commercial Dutch dairy herds.

Declining fertility in dairy cows is frequently suggested to arise from the occurrence of a more negative energy balance and/or the concomitant increased accumulation of triacylglycerol in the liver. Therefore, we performed a field study to assess the clinical effects of postpartum fatty liver in dairy cows on fertility and reproductive disease. Data were collected from 360 cows from nine dairy herds on fertility, diseases, and the liver triacylglycerol content on two occasions during lactation: 6 to 17 days and 38 to 50 days postpartum. The mean concentration of triacylglycerol in the liver was 54.6 mg/g from 6 to 17 days and 38.4 mg/g from 38 to 50 days postpartum. The probability of pregnancy was 30% lower for cows with higher contents of triacylglycerol in the liver compared to the probability for cows with low liver triacylglycerol (P = 0.049). The probability of estrus was also 35% lower for the cows with high triacylglycerol in the liver. This resulted in larger intervals between parturition and first heat and parturition and pregnancy for these cows. There was no effect observed on the first insemination conception rate. Given a certain level of triacylglycerol, recorded milk production had a positive effect on time to pregnancy. The incidences of endometritis, lochiometra and cystic ovarian follicles were not higher in cows with higher liver triacylglycerol contents. Endometritis was associated with a lower first insemination conception rate and more days open (chi2 = 4.26, P = 0.03 and T-test = -2.02, P= 0.04 respectively). We concluded that our results support the idea that differences in the negative energy balance or the accumulation of triacylglycerol in the liver of postpartum dairy cows affect fertility performance. The data also indicate that an increase in milk production has no negative impact on fertility as long as the amount of triacylglycerol in the liver remains the same.

Animals↗

PubMed2000

Safety of fluoxetine during the first trimester of pregnancy: a meta-analytical review of epidemiological studies.

BACKGROUND: This study was designed to examine whether there is an increased risk for major malformations following the use of fluoxetine during the first trimester of pregnancy. METHODS: Published and unpublished reports were identified through computerized and manual searches of bibliographical databases, reference lists from primary articles, and letters to editors, agencies, foundations and content experts. Meta-analysis was undertaken of prospective controlled and uncontrolled studies on the use of fluoxetine during first trimester of pregnancy. RESULTS: The pooled relative risk and 95% confidence interval for major malformations does not suggest an association between the use of fluoxetine during the first trimester and an increased risk of major malformations. Combination of controlled and uncontrolled studies shows a weighted risk of 26% (95% CI 1-4.2%). The summary odds ratio from the two controlled studies (OR = 1.33, 95% CI 0.49-3.58) was not significant. Homogeneity testing shows that the effect sizes are similar throughout all studies. Power analysis indicates that 26 controlled studies of similar size, would be required, to reverse this finding. CONCLUSIONS: The use of fluoxetine during the first trimester of pregnancy is not associated with measurable teratogenic effects in human.

Abnormalities, Drug-Induced↗

PubMed1990

Oral contraceptives and breast cancer. Review and meta-analysis.

To evaluate the relation between use of oral contraceptives and the incidence of breast cancer, the authors reviewed the epidemiologic literature and used quantitative methods to summarize the data. Study results for any use of oral contraceptives were pooled using a model that accounted for both interstudy and intrastudy variability. The authors also explored interstudy variability and modeled a duration-effect relation between oral contraceptive use and breast cancer. Case-control and follow-up studies were considered separately. Overall, the authors observed no increase in the risk of breast cancer for women who had ever used oral contraceptives, even after a long duration of use. These results were consistent across study design. However, data combined from case-control studies revealed a statistically significant positive trend (P = 0.001) in the risk of premenopausal breast cancer for women exposed to oral contraceptives for longer duration. This risk was predominant among women who used oral contraceptives for at least 4 years before their first term pregnancy (relative risk = 1.72; 95% confidence interval = 1.36 to 2.19). Additional study is required to determine whether this finding in a subgroup of exposed women is confirmed and whether the risk remains increased with advancing age.

Adult↗

PubMed2005

Breast cancer risk associated with genotypic polymorphism of the mitosis-regulating gene Aurora-A/STK15/BTAK.

Aneuploidy, an abnormal number of chromosomes, is relatively common and occurs early in breast cancer development. This observation supports a breast tumorigenic contribution of mechanisms responsible for maintaining chromosome number stability in which centrosomes play an essential role. We therefore speculated that the Aurora-A/STK15/BTAK gene, implicated in the regulation of centrosome duplication, may be associated with breast tumorigenesis. To test this hypothesis, we conducted a case-control study of 709 primary breast cancer patients and 1,972 healthy controls, examining single-nucleotide polymorphisms (SNPs), including a suggested functional Phe31Ile SNP, in Aurora-A. We were also interested in knowing whether any association between Aurora-A and breast cancer was modified by reproductive risk factors reflecting susceptibility to estrogen exposure. Our hypothesis is that, since estrogen is known to promote breast cancer development via its mitogenic effect leading to malignant proliferation on breast epithelium and since Aurora-A is involved in regulating mitosis, the discovery of a joint effect between the Aurora-A genotype and reproductive risk factors on cancer risk might yield valuable clues to the association of breast tumorigenesis with estrogen. Support for this hypothesis came from the following observations. (i) Two SNPs in Aurora-A were significantly associated with breast cancer risk (p < 0.05). (ii) Haplotype analyses, based on different combinations of multiple SNPs in Aurora-A, revealed a strong association with breast cancer risk; interestingly, the genotypic distribution of the suggested functional Phe31Ile SNP was not significantly different between breast cancer patients and controls, but the specific haplotype containing the putative at-risk Ile allele was more common in patients. (iii) This association between risk and putative high-risk genotypes was stronger and more significant in women thought to be more susceptible to estrogen, i.e., those with a longer interval between menarche and first full-term pregnancy. (iv) The protective effect conferred by a history of full-term pregnancy was significant only in women with a putative low-risk genotype of Aurora-A. Our study provides new findings supporting the mutator role of Aurora-A in breast cancer development, suggesting that breast cancer could be driven by genomic instability associated with variant Aurora-A, the tumorigenic contribution of which could be enhanced as a result of increased mitosis due to estrogen exposure.

Aurora Kinase A↗

PubMed1990

An epidemiologic study of thyroid cancer in Hawaii.

A population-based case-control interview study was designed to test the hypothesis that dietary iodine or the consumption of goitrogenic vegetables increases the risk of thyroid cancer. A total of 191 histologically confirmed cases (64 percent female) and 441 matched controls from five ethnic groups in Hawaii were available for analysis. Among women, intake of seafood (especially shellfish), harm ha (a fermented fish sauce), and dietary iodine were associated with an increased risk of cancer, whereas consumption of goitrogenic (primarily cruciferous) vegetables was associated with a decreased risk. Non-dietary risk factors included miscarriage (especially at first pregnancy), use of fertility drugs, family history of thyroid disease, obesity, and work as a farm laborer. The odds ratio for the combined effect of a high iodine intake and a first-pregnancy miscarriage was 4.8 (95 percent confidence interval [CI] = 1.2-19.2); and for high iodine intake and use of fertility drugs 7.3 (95 percent CI = 1.5-34.5). Among men, positive associations were found for obesity, work as a farm laborer, and a past history of benign thyroid disease. Although this study identified several dietary and non-dietary risk factors for thyroid cancer, it could not fully explain the exceptionally high incidence rates among Filipino women in Hawaii.

Adult↗

PubMed2005

Reproductive and dietary determinants of the age at menopause in EPIC-Heidelberg.

OBJECTIVES: The aim of the study was to explore the influence of reproductive and dietary factors on the age at menopause. METHODS: During follow-up of the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort in Heidelberg (median duration 5.8 years), 1009 women experienced natural menopause. They were compared to 3798 women who did not experience menopause. Baseline dietary intake was obtained by means of validated food frequency questionnaires. Data on reproductive history and medication was collected by means of questionnaires. Cox' proportional hazard models were applied in order to identify determinants of the age at natural menopause. RESULTS: Increasing age at first full term pregnancy and a longer time interval until occurrences of regular menses are associated with later onset of natural menopause. Compared to never smokers, current smokers have the risk of younger age at menopause. High carbohydrate consumption and high intake of vegetable, fibre and cereal products are inversely related to the age at natural menopause. Women with higher intake of total fat, protein and meat experienced a delayed onset of natural menopause. CONCLUSION: Age at natural menopause is influenced by lifestyle and dietary factors. Further studies including biological markers are needed to clarify these associations.

Adult↗

PubMed2001

Contraceptive efficacy and clinical performance of Nestorone implants in postpartum women.

The objective of this study was to evaluate the contraceptive efficacy and clinical performance of a Nestorone subdermal implant (NES) in the postpartum period. NES (n = 100) and Copper T intrauterine device (T-Cu; n = 100) acceptors initiated contraception at 8 weeks postpartum and were followed at monthly intervals during the first year and at 3-month intervals thereafter. Pregnancy rates, breastfeeding performance, infant growth, bleeding pattern, and side effects were assessed. Blood and milk NES concentration were measured. No pregnancy occurred in 2195 and 2145 woman-months of NES implant and T-Cu use, respectively. No effect of NES on lactation and infant growth and no serious adverse events were observed. Lactational amenorrhea was significantly longer in NES users (353 +/- 20 days) than in T-Cu users (201 +/- 11 days). More NES users (55.8%) experienced prolonged bleedings than did T-Cu users (36.2%). Concentrations of NES in breast milk ranged between 54-135 pmol/liter. The Nestorone implant is a highly effective contraceptive, safe for breastfed infants because the steroid is inactive by the oral route.

Adolescent↗

PubMed2000

Effect of tropically adapted sire breeds on preweaning growth of F1 Angus calves and reproductive performance of their Angus dams.

The objective of this study was to determine the effect of tropically adapted sire breeds on preweaning growth performance of F1 calves and on reproductive performance of their Angus dams. Angus (A) cows were bred in two consecutive years (1992 and 1993) by AI using semen from Brahman (B; Bos indicus; n = 10), Senepol (S; Bos taurus; n = 10), and Tuli (T; Sanga; n = 9) bulls. A total of 82 B x A, 85 S x A, and 91 T x A calves were born. The statistical model included the fixed effects of year, sire breed, calf sex, sire breed x calf sex, and cow parity and the random effect of sire within sire breed. Birth weight, weaning weight, 205-d adjusted weaning weight, ADG from birth to weaning, and hip height at weaning were greater (P < .001) for B x A calves than for S x A or T x A calves. Greater differences were detected between sexes for B x A than for S x A and T x A (for all traits sire breed x calf sex, P < .05). Sire breed affected (P < .01) the percentage of unassisted calvings (B x A, 87%; S x A, 98%; and T x A, 100%) and tended (P < .10) to affect the percentage of calves that survived until weaning (B x A, 90%; S x A, 94%; and T x A, 98%). Sire breed of calf did not affect (P > .10) length of gestation, and sire breed did not affect the interval from calving to first observed estrus or pregnancy in Angus dams. These results demonstrate that preweaning growth performance of B x A calves was greater than that of either S x A or T x A calves. However, use of Brahman sires on Angus dams led to calving problems and tended to reduce the percentage of calves that survived until weaning. Thus, heavier weaning weights of B x A calves would be an advantage for cow-calf producers marketing calves, but heavier birth weights and calving difficulty attributed to Brahman sires would be a disadvantage.

Adaptation, Physiological↗

PubMed1999

Familial occurrence of preeclampsia.

We conducted a cohort study on whether preeclampsia during the pregnancy of a mother is a risk factor for preeclampsia during the pregnancy of her daughter. Data from the Medical Birth Registry were combined with data from a local registry of births from 1955 to 1990. We could identify the births of 22,768 elder daughters and 2,959 younger daughters. These daughters had also experienced at least one delivery. If the mother had preeclampsia during her pregnancy with an elder daughter, then the elder daughter had an increased risk for preeclampsia in her first pregnancy (relative risk (RR) = 1.7; 95% confidence interval (CI) = 1.3-2.2). This increased risk persisted into the elder daughter's second pregnancy (RR = 1.7; 95% CI = 1.1-2.6). The risks for the daughters were also increased to a similar level if the mother had experienced preeclampsia in any other pregnancy. Furthermore, the risks were similarly elevated if only mothers with firstborn children were included in the analyses. Hence, preeclampsia during the pregnancy of a mother was a risk factor for development of preeclampsia during the pregnancy of her daughters; however, owing to a relatively small population attributable proportion, genetic predisposition explained only a minor part of the occurrence of preeclampsia in this population.

Birth Order↗

PubMed1997

Characteristics of women with and without breast augmentation.

OBJECTIVE: To compare selected characteristics of women with and without augmentation mammaplasty to identify differences between these 2 groups of women. DESIGN AND STUDY PARTICIPANTS: White women identified as controls in previously conducted population-based, case-control studies formed the study population for the present cross-sectional analysis (N=3570). MAIN OUTCOME MEASURE: Interview information on selected characteristics was compared between women who had received augmentation mammaplasty (n=80) and other women (n=3490) using the prevalence odds ratio (pOR) as the measure of association. RESULTS: Women with breast implants were more likely to drink a greater average number of alcoholic drinks per week (for > or =7 drinks vs 0 drinks: pOR=2.9, 95% confidence interval [CI]=1.5-5.5), be younger at first pregnancy (for age <20 years vs age 20-29 years: pOR=1.6, 95% CI=1.0-2.7), be younger at first birth (for age <20 years vs age 20-29 years: pOR=1.9, 95% C1=1.1-3.3), have a history of terminated pregnancies (for > or =1 termination vs 0 terminations: pOR=2.0, 95% CI=1.2-3.4), have ever used oral contraceptives (pOR=2.2, 95% CI=1.0-4.7), have ever used hair dyes (pOR=4.5, 95% CI=1.3-15.4), and have had a greater lifetime number of sexual partners (for > or =14 partners vs < or =4 partners: pOR=8.9, 95% CI=3.1-25.5) than other women. A history of smoking, lactation, high blood pressure, or thyroid disorders, as well as the number of pregnancies, full-term births, or miscarriages, differed little between women with and without implants. Women with breast augmentation were much less likely to be heavy than other women (for > or =74 kg vs <56 kg: pOR=0.1, 95% CI=0.03-0.3). CONCLUSION: The differences we found between women with and without breast implants suggest that consideration and evaluation of confounding factors in future studies will help to clarify some of the long-term health consequences of having breast implants.

Adult↗

PubMed1986

[Effect of bacterial lipopolysaccharide pyrogenal on the development of the Syrian hamster embryo].

Pyrogenal is injected to female hamsters (Mesocricetus auratus) at various time of pregnancy twice, with a 24 hour's interval: at first 100 or 50, and then--50 or 25 minimal pyrogenic doses. The embryos are examined on the 15th day of the intrauterine development by means of main teratologic methods. Pyrogenal injected on the 9th--10th day of the embryonal development produces hydrocephaly, micrognathia, retardation in development, hemorrhagic syndrome. Pyrogenal injected during some other time of pregnancy produces hemolysis of erythrocytes. This is proved by presence of hemosiderin in the foetal liver.

Abnormalities, Drug-Induced↗

PubMed1997

Caffeine intake and delayed conception: a European multicenter study on infertility and subfecundity. European Study Group on Infertility Subfecundity.

The effects of caffeine consumption on delayed conception were evaluated in a European multicenter study on risk factors of infertility. Information was collected retrospectively on time of unprotected intercourse for the first pregnancy and the most recent waiting time episode in a randomly selected sample of 3,187 women aged 25-44 years from five European countries (Denmark, Germany, Italy, Poland, and Spain) between August 1991 and February 1993. The consumption of caffeinated beverages at the beginning of the waiting time was used to estimate daily caffeine intake, which was categorized as 0-100, 101-300, 301-500, and > or = 501 mg. Risk of subfecundity (> or = 9.5 months) and the fecundability ratio, respectively, were assessed by logistic regression and Cox proportional hazard analyses, adjusting for age, parity, smoking, alcohol consumption, frequency of intercourse, educational level, working status, use of oral contraceptives, and country. A significantly increased odds ratio (OR) of 1.45 (95% confidence interval (CI) 1.03-2.04) for subfecundity in the first pregnancy was observed for women drinking more than 500 mg of caffeine per day, the effect being relatively stronger in smokers (OR = 1.56, 95% CI 0.92-2.63) than in nonsmokers (OR = 1.38, 95% CI 0.85-2.23). Women in the highest level of consumption had an increase in the time leading to the first pregnancy of 11% (hazard ratio = 0.90, 95% CI 0.78-1.03). These associations were observed consistently in all countries as well as for the most recent waiting time episode. The authors conclude that high levels of caffeine intake may delay conception among fertile women.

Adult↗

PubMed2005

The impact of interpregnancy interval and previous preterm birth on the subsequent risk of preterm birth.

OBJECTIVE: To examine the impact of the interpregnancy interval and a previous preterm birth on the subsequent risk of a preterm birth. METHODS: A retrospective analysis was conducted on a group of 4072 women who had at least two consecutive births, excluding multiple gestation, fetal anomalies, cervical incompetence, and stillbirth. Multivariate logistic regression was used to investigate the association between interpregnancy interval, preterm birth of the first child in the pair (index pregnancy), and the risk of a preterm birth of the second child in the pair (outcome pregnancy). RESULTS: Women with interpregnancy intervals of less than 12 months (odds ratio [OR] 1.3; 95% confidence interval [CI] 1.0-1.7) were at increased risks of preterm birth with the outcome pregnancy. Furthermore, there was an increased risk for a subsequent preterm birth in women who had a preterm birth in the index pregnancy (OR 4.2; 95% CI 3.0-6.0). The risk decreased as the interpregnancy interval increased, with a relatively low risk at 18 to 48 months; subsequently, it increased sharply. In contrast, women who had delivered their previous infants at term carried an increased risk of preterm birth with the outcome pregnancy only if the interval was less than 6 months. CONCLUSION: A difference was found in the impact of the interpregnancy interval on the subsequent risk of preterm birth between women with a prior preterm birth and those who previously delivered an infant at term.

Adult↗

PubMed2006

Community influenza activity and risk of acute influenza-like illness episodes among healthy unvaccinated pregnant and postpartum women.

This study investigated the relation between weekly levels of influenza activity and the risk of acute influenza-like illness episodes among 8,323 healthy pregnant and postpartum women enrolled in a Puget Sound region, Washington, health maintenance organization, Group Health Cooperative, between June 1991 and December 1997. The authors classified weeks between October and May for isolate activity level based on surveillance data for influenza, respiratory syncytial virus, parainfluenza, and adenovirus infection. Influenza-like illness episodes were identified from medical encounters assigned a diagnostic code consistent with a symptomatic influenza infection. The authors compared the occurrence of influenza-like illness episodes within each pregnancy stage for periods with varying levels of influenza isolate detection in the community. Repeated-measures logistic regression methods accounted for time-dependent factors. The adjusted strength of association between influenza exposure and influenza-like illness episodes increased as the pregnancy stage progressed (first trimester odds ratio = 1.12, 95% confidence interval: 0.79, 1.59; second trimester odds ratio = 1.30, 95% confidence interval: 0.97, 1.73; third trimester odds ratio = 1.84, 95% confidence interval: 1.31, 2.59; postpartum period odds ratio = 2.28, 95% confidence interval: 1.42, 3.68). Pregnancy stage modified the association between influenza activity and influenza-like illness episodes. Findings estimate that 20-43 pregnant/postpartum women would need to be vaccinated with an 80% effective vaccine to prevent one influenza-like illness episode.

Acute Disease↗

PubMed1998

Effect of injection of beta-carotene or vitamin E and selenium on fertility of lactating dairy cows.

Experiments tested whether supplemental antioxidants improved fertility. To test effects of beta-carotene, cows in a hot environment were injected with prostaglandin F2 alpha (PGF2 alpha) and were given 3 injections, i.m., of 800 mg beta-carotene or saline at Days -6 and -3 before the anticipated date of insemination and at insemination (n = 37-41 inseminated cows/group). There was no effect of beta-carotene on the proportion of cows detected in estrus following PGF2 alpha, timing of estrus after PGF2 alpha injection or pregnancy rate in inseminated cows. In a second trial, cows in a temperate climate received intramuscular injections of vitamin E (500 mg) and selenium (50 mg) at 30 d post partum (n = 97) or were untreated controls (n = 89). Treatment did not affect interval from calving to first insemination or the proportion of cows pregnant at first service, but it increased the pregnancy rate at second service (69.8 vs 52.1%; P = 0.07) and reduced services per conception (1.7 vs 2.0; P < 0.05) and interval from calving to conception (84.6 vs 98.1; P < 0.05). Thus, injection of vitamin E and selenium increased fertility in cattle that did not become pregnant at first service.

Animals↗