The term "elderly parturient" was defined in 1958 by the Council of International Federations of Obstetrics as "one aged 35 years or more at the first delivery" (1). Advanced maternal age has traditionally been defined as age > 35 years at delivery (2). Delayed childbirth has become a common phenomenon in the developed world as a result of social, educational, and economic factors (3). A woman's career priorities, advanced education, infertility, control over fertility, late and second marriages, and financial concerns may play a role in delaying childbearing (1, 4). In the United States during 1992 there were over 4,000,000 births, with 2000 live births to women 45 to 49 years of age (2, 5). In 1994, 45% of US college graduate women giving birth for the first time were older than 30 years of age, compared to 10% of US college graduate women in 1969 (6). With advances in assisted reproductive technologies and oocyte donation, births to women over 40 years of age are becoming common (7). Management of parturients of advanced maternal age requires an understanding of the effects of age, pre-existing comorbidities, and complications during pregnancy and delivery (7). Older age is associated inherently with a higher incidence of chronic disease (3). Older women are more likely than younger women to have hypertensive disorders, diabetes, placental complications, and cesarean delivery (8, 9). The anesthetic management of the parturient with advanced maternal age should be tailored to a given parturient who may have preexisting medical conditions, in addition to obstetric complications. This discussion will review maternal and fetal considerations in parturients of advanced maternal age.
Maternal morbidity and mortality increase with maternal age (10, 11). Hoyert et al. reported that from 1982-1997, maternal mortality rates were nearly three times higher for women 35-39 years of age compared to women 20-24 years of age, and nearly five times higher for women age 40 years and older compared to women 20-24 years of age (11). Infants of healthy older parturients have been shown to have a significantly higher incidence of low birth weight, preterm delivery, and intrauterine growth restriction (IUGR) (2, 12, 13). In addition, fetal chromosomal abnormalities begin to rise in number at approximately 35 years of age, rising sharply at 40 years of age with a peak occurring at 45 years of age (14-16). Genetic screening is commonly performed in older parturients to determine if the pregnancy will terminated . Thus, a number of studies actually report that the incidence of chromosomal abnormalities in neonates is the same or lower in parturients of advanced maternal age compared to younger parturients (17, 18). The incidence of spontaneous abortion increases in women > 35 years of age (14, 15, 19). Also, the incidence of stillbirth is higher in healthy women older than 35 years of age than in younger women (8, 12).
The association of an increased incidence of hypertension with increasing age in the nonpregnant state is continued when pregnancy occurs (14). Chronic hypertension is more common in parturients of advanced maternal age compared to younger parturients (2, 3, 9, 13, 15, 20, 21). Also, parturients with pre-existing hypertension have an increased incidence of preeclampsia, placental abruption, and IUGR (22). Obesity and diabetes increase the incidence of preeclampsia (23, 24). The incidence of preeclampsia is increased in both nulliparous and multiparous parturients of advanced maternal age (13, 18, 25, 26). One study reported that 17% of parturients over the age of 35 years develop preeclampsia (18).
Parturients of advanced maternal age have an increased incidence of uterine leiomyomata (27). Uterine leimyomata are independently associated with placental abruption, dysfunctional labor, fetal malpresentation, and cesarean delivery (27).
Abu-Heija et al found a high incidence of placental abruption (6.1%) in parturients >45 years of age compared to younger parturients (0.8%) (13). Parturients with a history of chronic hypertension, cigarette smoking, or prior stillbirth also have an increased incidence of placental abruption (8, 28). Abu-Heija et al reported an increased incidence of placenta previa (4.4%) in parturients > 45 years of age compared to younger parturients (1.6%) (13). Thus, appropriate intravenous access and availability of blood products must be confirmed in preparation for potential intrapartum and/or postpartum hemorrhage.
Parturients of advanced maternal age are more likely to have diabetes compared to younger parturients (2, 3, 18, 20, 21, 23). Pancreatic B cell function and insulin sensitivity fall with age (12). In fact, up to 16% of parturients of advanced maternal age have an abnormal glucose tolerance test (18).
Maternal weight, both prior to pregnancy and at term, increases with maternal age (21). Independent of maternal age, obesity increases the incidence of preeclampsia, diabetes, induction of labor, and cesarean delivery (23).
Fertility decreases with age. The increased utilization of assisted reproductive techniques, especially in women of advanced maternal age, has resulted in an increased incidence of multiple gestation. Multiple gestation is associated with preeclampsia, antepartum and postpartum hemorrhage, preterm delivery, cesarean delivery, low infant birth weight, and increased maternal and perinatal mortality (29).
Breech presentation is more common in parturients of advanced maternal age (2, 12, 30, 31). Dildy et al reported an incidence of 11% breech presentation in parturients > 45 years of age. Interestingly, this increased incidence of breech presentation may be secondary to uterine leiomyomata, which are increased in women of advanced maternal age (27).
Parturients of advanced maternal age are more likely to deliver prior to term and more likely to delivery at < 32 weeks gestation (12). Pugliese et al reported preterm delivery in 18% of women > 40 years of age compared to a 12% incidence of preterm delivery in younger women (17). The presence of multiple gestation also contributes to an increased incidence of preterm labor and delivery (27).
The incidence of cesarean delivery for dystocia increases with age (2, 3, 9, 11, 12, 13, 15, 26). Some postulate deteriorating myometrial function with increasing age as the etiology for dysfunctional labor in women of advanced maternal age (32). Popov et al observed that with advancing age in primiparous women, there was a progressive thickening of the muscular layer of myometrial arteries due to fibrosis which may ultimately lead to reduced uterine contractility (32, 33). The cesarean delivery rate is more than twice as high in parturients > 35 years of age than in women 20-29 years of age (34). Among nulliparous women > 35 years of age, cesarean delivery rates of 21-52% have been reported (17, 18, 30, 34). In addition, the incidence of emergency cesarean delivery is higher in parturients of advanced maternal age (32). This may be due to an increased incidence of placental abruption, placenta previa, breech presentation, preterm labor, amd multiple gestation in parturients of advanced maternal age.
As more women delay childbearing, older parturients constitute a large and growing fraction of our obstetric patient population. The parturient of advanced maternal age is a patient with a high risk of maternal and perinatal morbidity and mortality. Anesthesia care providers should be aware of the associated problems in this patient population so that appropriate anesthetic management plans can be formulated to ensure good maternal and perinatal outcomes.
Sumedha Panchal, MD
Assistant Professor, Department of Anesthesiology
Weill Medical College of Cornell University
New York, New York