Career women who put babies on hold until after 40, or even 45, will be reassured by new research from Tel Aviv University. Even though there are associated risks for babies when postponing child-bearing, the neonates can overcome them, says Prof. Yariv Yogev of Tel Aviv University's Sackler School of Medicine and the Hospital for Women at Rabin Medical Center.

Working as a clinician in Israel, a country that supports in vitro fertilization (IVF) in older women, Prof. Yogev and his colleagues investigated the outcomes for mothers of 45 or more and their children. They personally assessed adverse health risks so they could more effectively advise future patients of any foreseeable dangers. "I'd been an attending physician in a delivery ward to a woman over 60 who had twins. I wanted to know if it's ethical to treat older women like this — I wanted to know if it's safe for both mother and child," Prof. Yogev explains.

In a study published in the American Journal of Obstetrics & Gynecology, Prof. Yogev reports on evidence collected on more than 200 births in older women. Included in the study were 177 women over the age of 45 and 20 above the age of 50.

A natural center of older moms

There are more complications in pregnancies for older women, Prof. Yogev explains, but the risks are considerably lessened in a good birthing center. Most older women, he says, will deliver a healthy child, and the majority of complications that arise in women over 40 are health risks such as gestational diabetes or preeclampsia. For the most part these risks do not affect the newborn after three days have passed.

Frequent IVF cycles are covered by the social health insurance system in Israel, which provided Prof. Yogev with extensive data on pregnancy outcomes. Also, he says, a growing number of women past 50, when Israel's coverage stops, are opting to fly abroad for insemination by an egg donor.

While Prof. Yogev does not encourage waiting later than 40 to start having children naturally — the rates of female fertility drop considerably after this point — the results show that would-be mothers can still give birth to healthy babies even if mom is 45 or even 50.

Blessings and risks: The hard numbers

The complications that mothers over 40 can expect include a 300% greater chance for gestational diabetes and high blood pressure during their pregnancies. Older women also have higher rates of preterm births and placenta previa, a condition in which the placenta blocks the opening to the birth canal. Prof. Yogev's study found that nine percent of older moms had high blood pressure, which affects only 3% of younger mothers. And an advanced age shortened the pregnancy to less than 37 weeks, compared to the normal 40 week gestation period. Severe bleeding after birth, and metabolic problems in the newborns were additional risk factors found in greater rates among older moms.

After 50, the risks and complications in women became more severe. But the babies themselves, Prof. Yogev says, overcame the risks in the short term.

The study was conducted on women at Rabin Medical Center in Israel, where Prof. Yogev is a practicing gynaecologist/obstetrician.