Maternal, perinatal and infant outcome of spontaneous pregnancy in the sixth decade of life
Introduction
Women on their sixth decade of life are usually perimenopausal; the average age of menopause in Latin-America is 49.5 ± 5.5 years [1]. Fertility decreases in the climacteric woman as a consequence of decreased oocyte number, frequency and efficiency of ovulation, and coital activity [2], [3]. Although fertility decreases, some perimenopausal women maintain reproductive potential and may spontaneously conceive [2], [3], [4]. Pregnancy may also be sought by perimenopausal women through assisted reproduction by oocyte donation [3]. The problem here is that older women are getting pregnant however the fetal outcome for this selected group is uncertain.
Maternal and fetal risk of death or disease increase with advanced maternal age [5], [6], [7], [8]. We have previously reported increased rates of maternal, fetal and neonatal mortality and morbidity in pregnant women older than 40 years in our population [9], [10].
A group of special interest because of its rarity and perhaps very high maternal and perinatal risk is that of women in their sixth decade of life (50 years or older). They are occasionally included in case series of pregnancy after 40 [5], [6], [7], [8], [10] or 45 years old [7], [11], [12], but seldom reported as a discrete group. The results of prior series reporting pregnancy outcome on women older than 50 years old are summarized in Table 1. The largest cohort reported is 539 deliveries among mothers aged 50 and above; in this report, there was an increased risk of low and very low birth weight, small for gestational age, prematurity and fetal mortality compared to younger women [13]. Apparently half became pregnant with the aid of assisted reproduction. Two reports, one of 55 pregnancies (45 live births) after oocyte donation [14] and the other 58 pregnancies after assisted reproduction [15] in healthy older than 50 years women, revealed a perinatal risk similar to the general population. These investigators did observe an increased rate of pregnancy-induced hypertension and gestational diabetes [14], [15]. Another series of 17 pregnancies after oocyte donation in women aged 50–59 years reported good perinatal outcome but a 50% chance of maternal complications, mainly hypertension and diabetes [16]. Likewise the follow-up of 24 pregnancies after oocyte donation in women 50–64 years old revealed increased risks of preterm birth, low birth weight, diabetes mellitus, hypertension, and hospitalization [17]. Lastly, a series of a 58 healthy well-selected women aged 50–60 years achieving pregnancy by oocyte donation revealed no increase in the prevalence of diabetes and hypertension [18]. None of these modest series describe neonatal, post-neonatal or infant mortality. Interestingly, none included a maternal death.
We postulated that the reported experience is highly biased and different from that observed in spontaneous pregnancy of perimenopausal women who statistically should have a higher rate of pre-existing medical conditions that should worsen perinatal and maternal outcome. We tested our hypothesis by conducting a retrospective but population based investigation of Chilean women who gave birth after spontaneous pregnancy in its sixth decade of life.
Section snippets
Population
We included all deliveries occurred in Chile from January 1st 1990 to December 31st 2004. The study group consisted of all deliveries by women of 50 years or older; the control group consisted of all deliveries by women aged 20–34 years.
Design
This was a retrospective analysis of a population database obtained from the Annual Report of Demography and Vital Statistics of the Chilean National Institute of Statistics [19].
Outcomes
The primary outcome measure was the number of deliveries, number of live births,
Results
During the study period, 4,105,462 live born and 20,531 stillbirths were registered (total deliveries: 4,125,993). Within this cohort, there were 217 lives or stillbirths (0.005%) whose mothers were 50 years or older. All deliveries (live or stillborn) of women aged 20–34 [2,817,742 (68%)] constituted the control group (Table 2).
In the study group, there were 4 fetal deaths and 213 live born. Subsequently, 13 neonates, 9 post-neonates and 22 infants died. There were 15 births <2500 g, 2 <1500 g,
Discussion
Spontaneous pregnancy in the sixth decade is possible though rare. Pregnancies of women at this age are subject to a high risk of fetal, neonatal, post-neonatal and infant death.
Chile is acquiring the epidemiological characteristics of well-developed country. Women frequently delay the pregnancy until an age where maternal and fetal risks are increased [6], [20]. We previously observed an increasing number of our delivering women over the last 10 years were older than 40 years [9]. In developed
Financial support
This study was supported by a grant from Chilean Government FONDECYT 1020675.
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