Birth Risks Of Assisted Fertilization Linked To Infertility Causes Rather Than Procedure

Main Category:Pregnancy  Date:2008-8-18 17:52:00  view:40
The adverse perinatal outcomes associated with assisted fertilization(AF) in comparison to infants conceived spontaneously could beassociated with the causes of infertility rather than the procedureitself, according to an article released July 31, 2008 in TheLancet.

Increasingly, women in developing countries are delaying childbirthuntil an age when fertilization is decreased. As a result, more andmore are turning to assisted reproductive technologies to achievepregnancy. Assisted fertilization has been associated with an increasedrisk of adverse health outcomes in infants, but it is difficult toseparate the effects of the procedure itself from those that mightsimply be inherent in the birthing couple.

To help differentiate between these two effects, Dr Liv BenteRomundstad, St Olav's University Hospital, and Department of PublicHealth, Norwegian University of Science and Technology, Trondheim,Norway, and colleagues performed a population-based cohort study,selecting women over 20 who had at least one singleton pregnancyspontaneously as well as at least one after assisted fertilization. Theinfants were examined for birth weight, gestational age, the chances oflow birth weight given gestational age, premature birth, and perinataldeaths from 2,546 Norwegian women older than 20. These results werecompared with rates in 1,200,922 single birth controls and 8,229 AFcontrols.

It was found that AF conception was associated with:

• a lower average birth rate by 25 g
• a shorter gestation period by 2.0 days
• a 26% increased risk of being undersized for gestational age
• a 31% increased risk of perinatal death.聽

In the women for whom factors other than AF were controlled, that is,the women who had conceived both spontaneously and by AF, the AF babieshad:

• a lower average birth rate by 9 g
• a shorter gestation period by 0.6 days
• a similar risk of being undersized for gestational age
• a 200% increased risk of perinatal death.聽

The authors summarize and conclude: Birthweight, gestational age, andrisks for small gestational age babies, and preterm delivery, did notdiffer among infants of women who had conceived both spontaneously andafter assisted fertilisation. The adverse outcomes of assistedfertilisation that we noted compared with those in the generalpopulation could therefore be attributable to the factors leading toinfertility, rather than to factors related to the reproductivetechnology.

Dr Anja Pinborg, Copenhagen University Hospital, Denmark, andcolleagues, contributed an accompanying comment which states theimportance of this research: Considering that 14% of all newborns inEurope are conceived after assisted reproductive technology (ART),safety concerns are important. Reducing the number of multiple birthshas made improvements, but we need to gain a better biologicalunderstanding of the reasons why infertility and ovarian stimulationmay have adverse effects on infant health. Consequently, we have tocontinuously monitor the short and long-term risks of ART.

Effects of technology or maternal factors on perinatal outcomeafter assisted fertilisation: a population-based cohort study
Liv Bente Romundstad, Pal R Romundstad, Arne Sunde,Vidar von During,Rolv Skj忙rven, David Gunnell, Lars J Vatten
Published Online Lancet July 31, 2008
DOI:10.1016/S0140-6736(08)61041-7
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Written by Anna Sophia McKenney
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