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EDITORIALS: Zena Stein and Mervyn Susser The risks of having children in later life BMJ 2000; 320: 1681-1682 [Full text]

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Causes of fetal loss in older women

Ruth C Fretts   (23 June 2000)

The risks of having children in later life.

Alan Rodger   (19 July 2000)

Causes of fetal loss in older women 23 June 2000
Ruth C Fretts, Assistant Professor at Harvard Medical School Beth Israel Deaconess Medical Center Send response to journal: Re: Causes of fetal loss in older women	To the Editor: I commend the authors Andersen et al. for their comprehensive analysis of the effects of maternal age on the rate of fetal loss. We found that the causes of fetal death (500 grams or greater) for women of advanced maternal age has changed significantly over the past 30 years (1). In a large data set in Canada, we found during a study period of 1961 -74 that women 35 years of age or older , when compared to younger women, had 1.5 fold (CI 1.2-2.2) increased risk of experiencing a fetal death. This was largely due to an increased risk of lethal congenital anomalies (OR 3.2 CI 1.6-6.5). In a later time period (1978-95), while we found that the absolute rate of fetal deaths had decreased in all women, the risk of fetal death decreased less for older women (OR 1.8, CI 1.4-2.6). In this time period, it appears that older women are no longer experiencing an increased risk of fetal losses due to lethal anomalies(OR 0.2 CI 0.03-1.5). Presumably this is because older women are being screened for anomalies in first and second trimester and abortions are readily available. Interestingly we found that women 35 years of age or older had an increased risk of unexplained fetal deaths (OR 2.2, CI 1.3-3.8). These were fetal deaths which occurred in women without any known fetal or maternal risk factors (i.e. no maternal history of hypertension, diabetes, abruptio, infection, antepartum bleeding, fetal intrauterine growth retardation, or infection). Like Yudkin et al. we found that these fetal deaths occurred late in pregnancy with two thirds occuring after 35 completed weeks (2). In addition to advanced maternal age, we also found that first birth and obesity were significant predictors of this type of loss (3). With this information we are not only better able to counsel our older patients, but we also may have the opportunity to screen women at risk late in pregnancy in an attempt to reduce these unfortunate late fetal deaths. Ruth C Fretts, MD, MPH Assistant Professor Harvard Medical School, Beth Israel Deaconess Medical Center, Boston MA, 02214 1. Fretts RC, Usher RH, Causes of fetal death in women of advanced maternal age. Obstet Gynecol 1997;89:40-5. 2. Yudkin PL, Wood L, Redman CWG. The risk of unexplained fetal death at different gestational ages. Lancet 1987:1:1192-4. 3.Huang DY, Usher RH, Kramer MS, Yang H, Morin L, Fretts RC. Determinants of unexplained featl deaths. Obstet Gnecol 2000;95:215-21.
The risks of having children in later life. 19 July 2000
Alan Rodger Send response to journal: Re: The risks of having children in later life.	Editor - It is a pity that Stein and Susser confined their critique on the biological disadvantages of having children in later life 1. to matters obstetrical. While it is debatable that their claim that such risks as they and Andersen et al describe 2. are outweighed by the possibility that late pregnancy children may do better at school, there are other biological risks that should also be considered. One such is the long known fact that the risk of developing breast cancer increases in a woman with her age at first full term pregnancy. There is almost a 2.5 fold difference in the risk of breast cancer between women who have their first child before 20 and those whose first full term pregnancy is after 30 years of age. As possibilities and demands for having children later in life increase the whole range of risks need to be explained. Professor Alan Rodger Director of Radiation Oncology, William Buckland Radiotherapy Centre. References: 1. Stein Z and Susser M. The risks of having children in later life. BMJ. 2000 ; 320 : 1681-2 2. Andersen A-MN, Wohlfahrt J, Christens P, Olsen J, Melbye M. Maternal age and fetal loss : population based register linkage study. BMJ 2000 ; 320 : 1708 - 12. 3. Kelsey JL, Gammon MD, John EM. Reproductive factors and breast cancer. Epidemiologic Reviews. 1993 ; 15 : 36 - 47 4. NHMRC National Breast Cancer Centre. Summary of risk factors for breast cancer. 1999. Chapt 4 : 17 - 21. NHMRC National Breast Cancer Centre. Sydney.