Subfertility and the risk of low birth weight.
OBJECTIVE
We evaluated the association between subfertility and low birth weight infants.


METHODS
Women in this analysis participated in a cross-sectional investigation of maternal risk factors for adverse pregnancy outcomes.


METHODS
Medical and obstetric history and life style information were obtained from women who delivered at the Boston Hospital for Women, 1977 to 1980.


METHODS
Our analysis was restricted to nondiabetic married women who planned their pregnancies and subsequently delivered viable singletons (3,622). The 644 "subfertile" women (no conception during a year of unprotected intercourse) were compared with 2,978 "fertile" women (conception within 1 year).


METHODS
The relative risk of low birth weight was estimated using the cumulative incidence risk ratio.


RESULTS
After adjusting for confounding, the relative risk of delivering a low birth weight infant (less than 2,500 g) for subfertile women versus fertile women was 1.9 (95% confidence interval [CI], 1.3 to 2.8). The adjusted relative risk of delivering a term low birth weight (intrauterine growth retarded) infant was 2.3 (95% CI, 1.2 to 4.4).


CONCLUSIONS
In these data, subfertility is a predictor for low birth weight. The association may result from endocrinological, immunological, cervical, or other factors that interfere with optimal fetal growth.
Harvard School of Public Health, Boston, Massachusetts.
M A
MA
Williams
M B
MB
Goldman
R
R
Mittendorf
R R
RR
Monson
D003069:Coffee / Q000009:adverse effects; D005260:Female; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007247:Infertility, Female / Q000150:complications*; D011247:Pregnancy; D012044:Regression Analysis; D012307:Risk Factors
D003069:Coffee