Reprint of: Estimates of human fertility and pregnancy loss

Zinaman, Michael J.; Clegg, Eric D.; Brown, Charles; O’Connor, John F.; Selevan, Sherry G.

doi:10.1016/j.fertnstert.2019.08.096

Cited by 92 publications

(108 citation statements)

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“…Since appropriate basis functions may be difficult to specify and the number of basis functions can be very large or even infinite, we choose to use the dual representation in this article. Common kernel functions include (i) the polynomial kernel: K(Z 1 ,Z 2 ) = (Z 1Z2 + ) d , where and d are tuning parameters; (ii) the Gaussian kernel: 2 and is the tuning parameter; and (iii) the identity-by-state kernel 22 :…”

Section: Modelmentioning

confidence: 99%

“…Among the few prospective cohort studies with preconception enrollment of women or couples with follow-up for 12 months of trying, the incidence of infertility ranges between 13% 1 and 18%. 2 The implications of infertility for health across the lifespan are recognized, 3 as are the accompanying economic, psychological, and social implications, as recently reviewed. 4 There is a growing interest in associations between exposures to various environmental pollutants and infertility.…”

Section: Introductionmentioning

confidence: 99%

“…An environmental etiology of infertility has been postulated in light of several persistent and nonpersistent environmental chemicals, measured in both female and male partners, being associated with diminished couple fecundity, as recently summarized. 2,[4][5][6] A comprehensive understanding of these relationships can inform public health policy and provide guidelines to couples who are actively seeking pregnancy. As a motivating example, we considered the Longitudinal Investigation of Fertility and the Environment (LIFE) Study, a prospective cohort study designed to investigate environmental influences on human fecundity and fertility.…”

Section: Introductionmentioning

confidence: 99%

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A weighted kernel machine regression approach to environmental pollutants and infertility

Zhang

Chen

Liu

et al. 2018

Statistics in Medicine

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In epidemiological studies of environmental pollutants in relation to human infertility, it is common that concentrations of a large number of exposures are collected in both male and female partners. Such a couple‐based study poses some new challenges in statistical analysis, especially when the effect of the totality of these chemical mixtures is of interest, because these exposures may have complex nonlinear and nonadditive relationships with the infertility outcome. Kernel machine regression, as a nonparametric regression method, can be applied to model such effects, while accounting for the highly correlated structure within and across exposures. However, it does not consider the partner‐specific structure in these study data, which may lead to suboptimal estimation for the effects of environmental exposures. To overcome this limitation, we developed a weighted kernel machine regression method (wKRM) to model the joint effect of partner‐specific exposures, in which a linear weight procedure is used to combine the female and male partners' exposure concentrations. The proposed wKRM is not only able to reduce the number of analyzed exposures but also provide an overall importance index of female and male partners' exposures in the risk of infertility. Simulation studies demonstrate good performance of the wKRM in both estimating the joint effects of exposures and fitting the infertility outcome. Application of the proposed method to a prospective infertility study suggests that the male partner's exposure to polychlorinated biphenyls might contribute more toward infertility than the female partner's.

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Section: Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A weighted kernel machine regression approach to environmental pollutants and infertility

Zhang

Chen

Liu

et al. 2018

Statistics in Medicine

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“…Of note, the incidence of pregnancy loss in this preconception cohort (28%) is comparable to estimates from prior preconception cohort studies (26%-31%). 1,2,19 Choice of time scale…”

Section: Strengths Of the Studymentioning

confidence: 99%

Time‐Varying Effects of Signs and Symptoms on Pregnancy Loss <20 Weeks: Findings from a Preconception Prospective Cohort Study

Sapra¹,

Louis

Sundaram

et al. 2017

Paediatric Perinatal Epid

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Background: Although pregnancy loss affects one-third of pregnancies, the associated signs/symptoms have not been fully described. Given the dynamic nature of maternal physiologic adaptation to early pregnancy, we posited the relationships between signs/symptoms and subsequent loss would vary weekly. Methods: In a preconception cohort with daily follow-up, pregnancies were ascertained by self-administered sensitive home pregnancy tests on day of expected menses. We evaluated the effects of weekly time-varying signs/symptoms (including vaginal bleeding, lower abdominal cramping, and nausea and/or vomiting) on pregnancy loss <20 weeks in Cox proportional hazards models and calculated the week-specific probability of loss by the presence/absence of each sign/symptom. Results: Of 341 pregnancies ascertained by home pregnancy test, 95 (28%) ended in loss. Relationships between signs/symptoms and loss varied across time since first positive pregnancy test. In the first week following pregnancy confirmation, when many losses occurred, bleeding [hazard ratio (HR) 8.7, 95% confidence interval (CI) 4.7, 16.0] and cramping (HR 1.8, 95% CI 1.2, 2.7) were associated with loss even when accompanied by nausea and/or vomiting (HR 5.2, 95% CI 2.6, 10.5). After the second week, new relationships emerged with nausea and/ or vomiting inversely associated (HR range 0.6-0.3, all 95% CI upper bounds <1.00) and bleeding no longer associated with loss. Probabilities of loss of ranged from 78% (95% CI 59%, 96%) with bleeding present in week 1 to 8% (95% CI 5%, 12%) with nausea/vomiting present in week 5. Conclusions: Relationships between signs/symptoms and pregnancy loss vary in early pregnancy possibly reflecting maternal physiologic response.

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“…In fact, the causes of spontaneous abortion in the first trimester are multivariate, and the most common cause is chromosomal abnormalities or exposure to teratogens. 12 The risk of pregnancy loss decreases with increasing gestational age and is relatively low after 15 weeks of gestation. 13 Obviously, many abnormal conditions will increase the risk of spontaneous abortion in the first trimester.…”

Section: Introductionmentioning

confidence: 99%

Comparison of subsequent pregnancy outcomes after surgery for adnexal masses performed in the first and second trimester of pregnancy

Zou

Zhu

et al. 2019

Intl J Gynecology & Obste

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Objective:To determine whether surgery for adnexal masses in the first trimester of pregnancy affects subsequent pregnancy outcomes compared to surgery in the second trimester.Methods: Data were retrospectively reviewed from women who underwent adnexal mass surgery before 26 weeks of gestation at a university hospital between July 2008 and June 2018. Women who underwent surgery in the first trimester were classified as group 1 (n=78) and those in the second trimester were classified as group 2 (n=48).Information on clinical characteristics and pregnancy outcomes was obtained from medical records and follow-up interviews and compared between two groups.Results: There were no differences in age, parity, mass size, laparoscopy, and operation time between the two groups. A total of 98 cases were confirmed as ovarian torsion, including 72 cases in group 1 and 26 cases in group 2. Accordingly, adnexectomy was performed more often in group 1 (P=0.002). No significant differences concerning the rate of abortion, preterm birth, or cesarean delivery were found.Conclusion: Surgery for adnexal masses performed in the first trimester is almost as safe as that in the second trimester. Surgery should be performed for women with a complex adnexal mass in the first trimester to avoid unfavorable complications. K E Y W O R D SAdnexal masses; Adnexal torsion; First trimester; Pregnancy outcomes; Second trimester; Surgery During the study period, a total of 160 women underwent surgery for adnexal masses before 26 weeks of gestation (Fig. 1). Among them, six women did not want to continue the pregnancy and received aspiration and curettage. For two women, the pregnancy was terminated by intraamniotic injection of ethacridine lactate because of fetal malformation (one for Down syndrome and the other for serious hydronephrosis of the fetus). The remaining 152 women continued the pregnancy, including 26 women lost to follow-up. Finally, 126 (82.9%) women met the inclusion criteria. In total, 78 cases were included in group 1 and 48 cases were included in group 2. The median age of gestation at the time of surgery was 9 weeks in group 1 and 15 5/7 weeks in group 2.Data showing the patients' characteristics are shown in Table 1.There was no difference in terms of maternal age, parity, or adnexal mass size between the two groups. Significantly more emergency surgeries were performed in group 1 compared with group 2 (75 [96.2%] vs 29 [60.4%], P<0.001). There were more twin pregnancies and more patients conceived through assisted reproductive technologies (ART) in group 1 (P=0.008 and P=0.007, respectively).The characteristics of the surgical procedure are shown in Table 2.There were no significant differences between the two groups regarding use of laparoscopy or operation time. However, surgical indications were significantly different. Suspected ovarian torsion occurred significantly more frequently in cases in group 1 (75 [96.2%], P<0.001), while a persistent mass was more frequent in group 2 (19 [39.6%], P<0.001). A total of 98 cases we...

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Reprint of: Estimates of human fertility and pregnancy loss

Cited by 92 publications

References 0 publications

A weighted kernel machine regression approach to environmental pollutants and infertility

A weighted kernel machine regression approach to environmental pollutants and infertility

Time‐Varying Effects of Signs and Symptoms on Pregnancy Loss <20 Weeks: Findings from a Preconception Prospective Cohort Study

Comparison of subsequent pregnancy outcomes after surgery for adnexal masses performed in the first and second trimester of pregnancy

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