Conceptions after age 35 currently comprise approximately 15 percent ofpregnancies in the United Stares (Martin, 2012). By contrast, these older women are more likely to request preconceptional counseling, either because of postponed pregnancy with a desire to optimize outcomes or because of plans to undergo infertility treatment. Some studies-including data from Parland Hospital presented in Figure 8-3 indicate that ater age 35, the risks for obstetrical complications and for perinatal morbidity and mortality rise (Cunningham, 1995; Waldenstrom, 2015). he older woman who has a chronic illness or who is in poor physical condition usually has readily apparent risks. For rhe physicallyfit woman without medical problems, however, the risks are much lower than previously reported.
Overall, the maternal mortality rate is higher in women aged 35 and older. Compared wirh women in rheir 20s, women aged 35 to 39 are 2.5 times more likely and women aged 40 or older are 5.3 times more likely to sufer pregnancy-related mortality (Geller, 2006). Creanga and coworkers (2015) analyzed pregnancy-related deaths in the United States for 2006 through 2010. Although women older than 35 years contributed less than 15 percent of all live births, they constituted 27 percent ofmaternal deaths. For the fetus, maternal age-related risks primarily stem from: (1) indicated preterm delivery for maternal complications such as hypertension and diabetes, (2) spontaneous preterm birth, (3) fetal growth disorders related to chronic maternal disease or multifetal gestation, (4) fetal aneuploidy, and (5) pregnancies resulting from assisted reproductive technology.
Recall that older women have subfertility problems. And although the incidence of dizygotic twinning increases with maternal age, the more important cause of multifetal gestation in older women follows the use ofassisted reproductive technology (ART) and ovulation induction. Indeed, according to the CDC, 30 to 40 percent ofall multifetal gestations in the United States in 2012 were conceived with the use ofART (Sunderan, 2015). Morbidity and mortality with multifetal pregnancies stem from preterm delivery. Other obstetrical morbidities, such as placenta previa, abruption, and preeclampsia, are also risks associated with these conceptions (Lukes, 2017; Qin, 2016).
Finally, experience has accrued that links ART to higher major congenital malformation rates. Davies and colleagues (2012) reported that of 308,974 births in South Australia, 8.3 percent ofneonates conceived byART had major birth defects.
In this analysis, after adjustment for maternal age and other risk factors, intracytoplasmic injection continued to be associated with a signiicantly elevated risk for malformations, but in vitro fertilization did not.
Parental history and experiences-paternal and maternal-can exert efects through epigenomic information not contained in the DNA sequence. Examples include variations in sperm and oocyte cytosine methylation and other mechanisms (Cedars, 2015; Lane, 2014). Perhaps one example is the possible link between increasing paternal age and complex neuropsychiatric conditions (Malaspina, 2015). Finally, the incidence of genetic diseases in ofspring caused by new autosomal-dominant mutations in older men is increased. Still, the incidence is low (Chap. 13, p. 265). Accordingly, targeted sonographic examination performed solely for advanced maternal or paternal age is controversial.