Conception, early pregnancy loss, and time to clinical pregnancy: a population-based prospective study

Wang, Xiaobin; Chen, Changzhong; Wang, Lihua; Chen, Dafang; Guang, Wenwei; French, Jonathan

doi:10.1016/s0015-0282(02)04694-0

Cited by 506 publications

(378 citation statements)

References 11 publications

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“…Previous studies on monitored pregnancies demonstrate that up to 30% of all pregnancies end with a fetal loss (spontaneous abortion or early pregnancy loss) (22). However, in our study, we could only account for those fetal losses that were reported by the patients.…”

Section: Discussionmentioning

confidence: 97%

The influence of fetal loss on the presence of fetal cell microchimerism: A systematic review

Khosrotehrani¹,

Johnson²,

Lau³

et al. 2003

Arthritis & Rheumatism

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Objective. Fetal cells enter the maternal circulation during most pregnancies. Their persistence for years occurs in only some women and has been associated with several autoimmune diseases such as systemic sclerosis. The objective of this study was to determine whether pregnancy history influences the persistence of fetal microchimeric cells.Methods. We reviewed all reports of studies on fetal cell microchimerism, defined as male DNA in maternal tissue, that describe individual pregnancy histories, disease diagnoses, and microchimerism status. The total numbers of pregnancies, births, and sons, the history of fetal loss (spontaneous abortion and elective termination), and the presence of a maternal autoimmune disease were tested as factors potentially associated with persistent microchimerism.Results. One hundred twenty-four subjects from 11 studies met the inclusion criteria. Only fetal loss was significantly associated with the presence of microchimerism (odds ratio 2.4, 95% confidence interval 1.2-6.0).Conclusion. These results suggest that fetomaternal cell trafficking following fetal loss may be important for the engraftment of microchimeric cells in maternal tissue. This may be due to an increased amount of fetomaternal transfusion or to transfer of a cell type that is more likely to engraft. We recommend that investigators in future studies on microchimerism report detailed pregnancy information, since these data are critical for the understanding of factors that influence the development of fetal cell microchimerism.

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Section: Discussionmentioning

confidence: 97%

The influence of fetal loss on the presence of fetal cell microchimerism: A systematic review

Khosrotehrani¹,

Johnson²,

Lau³

et al. 2003

Arthritis & Rheumatism

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“…Studies from 1988 63 onwards have produced more consistent data indicating early/occult loss of approximately 20% ( Figure 3). In the three largest studies 63, 66, 70 pregnancies were clinically recognised only if they lasted ≥6 weeks after the onset of the last menstrual period 66, 75 . Hence, early pregnancy losses in these studies included those lost up to approximately two weeks after a missed menstrual period: this may influence comparison of study results 34, 73 .…”

Section: What the Data Saymentioning

confidence: 99%

Early embryo mortality in natural human reproduction: What the data say

Jarvis

2016

F1000Res

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It is generally accepted that natural human embryo mortality during pregnancy is high – losses of 70% and higher from fertilisation to birth are frequently claimed. The first external sign of pregnancy occurs two weeks after fertilisation with a missed menstrual period. Establishing the fate of embryos before this is challenging, and hampered by a lack of data on the efficiency of fertilisation under natural conditions. Four distinct sources are cited to justify quantitative claims regarding embryo loss: (i) a hypothesis published by Roberts & Lowe in The Lancet is widely cited but has no quantitative value; (ii) life table analyses give consistent assessments of clinical pregnancy loss, but cannot illuminate losses at earlier stages of development; (iii) studies that measure human chorionic gonadotrophin (hCG) reveal losses in the second week of development and beyond, but not before; and (iv) the classic studies of Hertig and Rock offer the only direct insight into the fate of human embryos from fertilisation under natural conditions. Re-examination of Hertig’s data demonstrates that his estimates for fertilisation rate and early embryo loss are highly imprecise and casts doubt on the validity of his numerical analysis. A recent re-analysis of hCG study data suggests that approximately 40-60% of embryos may be lost between fertilisation and birth, although this will vary substantially between individual women. In conclusion, it is clear that some published estimates of natural embryo mortality are exaggerated. Although available data do not provide a precise estimate, natural human embryo mortality is lower than is often claimed.

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“…We felt this choice was justified as conception delay has been empirically shown to be a very good marker of identifying which couples will need clinical evaluation and/or treatment. While there have only been a few studies that have followed couples from discontinuing contraception through 12 months of trying, the data demonstrate that 76–90% of couples who do become pregnant do so within the first 6 months of trying (Gnoth et al ., 2003; Wang et al ., 2003; Buck Louis et al ., 2009, 2011). Moreover, clinical guidance suggests that couples seek care if not pregnant within 6 months of trying when the female partner is 35+ years of age.…”

Section: Resultsmentioning

confidence: 99%

“…Still, important limitations need to be considered including our reliance on 24‐h motility measures in light of at home semen collection, the potential for chance findings and residual confounding given the study's observational design. Also, we opted to use analytical techniques for impaired fecundity (time‐to‐pregnancy > 6 cycles) rather than infertility (time‐to‐pregnancy > 12 cycles), given that most (68–90%) couples trying for pregnancy do so within 6 months as observed in prospective pregnancy studies with preconception enrolment and 12 months of follow‐up (Gnoth et al ., 2003; Wang et al ., 2003; Buck Louis et al ., 2009, 2014). Also, couples may not wait 12 months before seeking clinical care.…”

Section: Resultsmentioning

confidence: 99%

A data‐driven search for semen‐related phenotypes in conception delay

2016

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SummarySperm count, morphology, and motility have been reported to be predictive of pregnancy, although with equivocal basis prompting some authors to question the prognostic value of semen analysis. To assess the utility of including semen quality data in predicting conception delay or requiring >6 cycles to become pregnant (referred to as conception delay), we utilized novel data‐driven analytic techniques in a pre‐conception cohort of couples prospectively followed up for time‐to‐pregnancy. The study cohort comprised 402 (80%) male partners who provided semen samples and had time‐to‐pregnancy information. Female partners used home pregnancy tests and recorded results in daily journals. Odds ratios (OR), false discovery rates, and 95% confidence intervals (CIs) for conception delay (time‐to‐pregnancy > 6 cycles) were estimated for 40 semen quality phenotypes comprising 35 semen quality endpoints and 5 closely related fecundity determinants (body mass index, time of contraception, lipids, cotinine and seminal white blood cells). Both traditional and strict sperm phenotype measures were associated with lower odds of conception delay. Specifically, for an increase in percent morphologically normal spermatozoa using traditional methods, we observed a 40% decrease in conception delay (OR = 0.6, 95% CI = 0.50, 0.81; p = 0.0003). Similarly, for an increase in strict criteria, we observed a 30% decrease in odds for conception delay (OR = 0.7, 95% CI = 0.52, 0.83; p = 0.001). On the other hand, an increase in percent coiled tail spermatozoa was associated with a 40% increase in the odds for conception delay (OR = 1.4, 95% CI = 1.12, 1.75; p = 0.003). However, our findings suggest that semen phenotypes have little predictive value of conception delay (area under the curve of 73%). In a multivariate model containing significant semen factors and traditional risk factors (i.e. age, body mass index, cotinine and ever having fathered a pregnancy), there was a modest improvement in prediction of conception delay (16% increase in area under the curve, p < 0.0002).

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Conception, early pregnancy loss, and time to clinical pregnancy: a population-based prospective study

Cited by 506 publications

References 11 publications

The influence of fetal loss on the presence of fetal cell microchimerism: A systematic review

The influence of fetal loss on the presence of fetal cell microchimerism: A systematic review

Early embryo mortality in natural human reproduction: What the data say

A data‐driven search for semen‐related phenotypes in conception delay

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