Conception, early pregnancy loss, and time to clinical pregnancy: a population-based prospective study.
OBJECTIVE
To examine rates of conception and pregnancy loss and their relations with time to clinical pregnancy and reproductive outcomes.


METHODS
A prospective observational study.


METHODS
Population-based cohort in China.


METHODS
Five hundred eighteen healthy newly married women who intended to conceive. Upon stopping contraception, daily records of vaginal bleeding and daily first-morning urine specimens were obtained for < or =1 year or until a clinical pregnancy was achieved. Daily urinary hCG was assayed to detect early pregnancy loss (EPL).


METHODS
None.


METHODS
Conception, pregnancy loss, and time to clinical pregnancy.


RESULTS
The conception rate per cycle was 40% over the first 12 months. Of the 618 detectable conceptions, 49 (7.9%) ended in clinical spontaneous abortion, and 152 (24.6%) in EPL. Early pregnancy loss was detected in 14% of all the cycles without clinically recognized pregnancy, but the frequencies were lower among women with delayed time to clinical pregnancy. Early pregnancy loss in the preceding cycle was associated with increased odds of conception (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.8-3.9), clinical pregnancy (OR, 2.0; 95% CI, 1.3-3.0), and EPL (OR, 2.4; 95% CI, 1.4-4.2) but was not associated with spontaneous abortion, low birth weight, or preterm birth in the subsequent cycle.


CONCLUSIONS
We demonstrated substantial EPL in the non-clinically pregnant cycles and a positive relation between EPL and subsequent fertility.
Wang
Xiaobin
X
Department of Pediatrics, Boston University School of Medicine and Boston Medical Center, Massachusetts, USA. xbwang@bu.edu
Chen
Changzhong
C
Wang
Lihua
L
Chen
Dafang
D
Guang
Wenwei
W
French
Jonathan
J
D000022:Abortion, Spontaneous / Q000453:epidemiology*; D000328:Adult; D002681:China / Q000453:epidemiology; D006063:Chorionic Gonadotropin / Q000652:urine; D015331:Cohort Studies; D005260:Female; D005306:Fertilization; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D013997:Time Factors
D006063:Chorionic Gonadotropin