RISK OF PRETERM DELIVERY AND LOW BIRTH WEIGHT
IN SINGLETON PREGNANCIES CONCEIVED BY WOMEN
WITH AND WITHOUT A HISTORY OF INFERTILITY
Loretta B. Camarano
Aims: The objective of this study was to determine predictors of low birth weight (LBW) and preterm delivery (PTD) in singleton pregnancies conceived by women with a history of infertility compared to singleton pregnancies conceived spontaneously by fertile woman.
Methods: Data were collected at eleven infertility clinics in Northern California. Using a retrospective cohort design, record review was conducted on women who carried singleton pregnancies to greater than or equal to 20 weeks gestation between 1994 and 1998. These women were stratified by method of conception: women who conceived using infertility treatment (n=542), women who conceived naturally following a history of infertility (n=441), and fertile women (n= 1008) identified through California Vital Statistics records. Logistic regression was used to determine whether an association exists between LBW or PTD and infertility or infertility treatment compared to fertile women, controlling for potential confounding variables.
Results: There was no significant difference in the frequency of PTD between the three groups of women; however there was a significant difference in the frequency of LBW between the three groups of women (p< .05). 10.8 % of women in the infertile treatment group, 8.6% of women in the infertile without treatment group and 6.4% of women in the fertile group delivered a LBW infant. Women with a history of infertility who had treatment were 1.55 (CI 1.03, 2.34) times more likely to have a LBW infant compared to the fertile group controlling for maternal age, nulliparity, gestational diabetes, and obesity. There was no significant increased odds of delivery of a LBW infant for the infertile without treatment group compared to the fertile group, controlling for maternal age, nulliparity, gestational diabetes, and obesity. Nulliparity was a significant independent predictor of LBW (OR 1.51, CI 1.07, 2.14) in all three groups when controlling for maternal age, gestational diabetes and obesity regardless of fertility conception status.
Conclusion: Women with a history of infertility who undergo infertility treatment and conceive a singleton pregnancy are not at increased risk of preterm delivery but may be at increased risk for having a LBW infant.