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Embryo biopsy does not affect early growth and risk of congenital malformations in PGD/PGS babies

July 08, 2008

Barcelona, Spain: A study of 70 singleton babies born after preimplantation genetic diagnosis and screening has shown that the procedure does not adversely affect their early growth and risk of congenital malformations.

The lead researcher, Professor Maryse Bonduelle, told the 24th annual meeting of the European Society of Human Reproduction and Embryology in Barcelona today (Tuesday): "These findings are very reassuring for the children, parents and clinicians involved in PDG/PGS treatments. They show that embryo biopsy in PGD and PGS had no adverse impact on singletons' growth or medical outcomes."

PGD/PGS is an invasive procedure that involves removing cells from the embryo before it is transferred to the mother's uterus and testing them for specific genetic disorders (such as cystic fibrosis and Duchenne muscular dystrophy). Doctors then select only the unaffected embryos to transfer. Until now, little was known about the effect on the early growth and clinical outcomes of children born after embryo biopsy.

Prof Bonduelle, head of the Centre for Medical Genetics at Universitair Ziekenhuis Brussel (Brussels, Belgium), and her colleagues compared 70 babies born after PGD/PGS with equal numbers of babies born after ICSI (intracytoplasmic sperm injection) or spontaneously conceived (SC).

They found no difference between the three groups with regard to weight, height and head circumference at birth and age two, or in rates of growth. PGD/PGS children were born more frequently after caesarean section than ICSI children, but had no more congenital malformations, hospital admissions or surgical interventions than did the ICSI or SC babies. Although the PGD/PGS children underwent more medical investigations, the number of abnormal results arising from these investigations was not significantly different to the other two groups.

The PGD/PGS children did have a lower body mass index (BMI) at age two than did the SC children. Prof Bonduelle said the reason for this might have something to do with the babies' diet: "We found that mothers who conceived after PGD/PGS worked less (working 63% of the time) than the ICSI mothers (working 77% of the time) and SC mothers (working 83% of the time); PGD/PGS children were less frequently in day care centres. We speculate that different, more healthy food might have been given to PGD/PGS children by the parents, given the finding that their mothers stayed at home more frequently, and this may be the reason for the healthier BMI."

"Complications of pregnancy and older parental age were more present in the PGD/PGS and ICSI groups, but these are both factors that are known to be present more frequently in mothers after assisted reproduction technology," said Prof Bonduelle. "Mothers and fathers of SC babies were significantly younger at delivery compared to the other two groups, and this also contributes to fewer pregnancy complications."

Other work published this year by the same research group has shown that there was no difference between the PGD/PGS, ICSI and SC children in other developmental areas, such as motor, mental, and socio-emotional development and language. Nor did the parents differ in terms of parental stress and health.

The researchers are continuing their study of PGD/PGS children as, so far, there are insufficient numbers to draw firm conclusions about any differences in major malformation rates. Two PGD/PGS children, one ICSI child and two SC children had major malformations. In the PGD/PGS group, one child suffered from a ventricular septum defect (a heart problem) and another child had hemivertebrae with gibbus (a malformation of the vertebrae causing a hump). One child from the ICSI group born at 39 weeks underwent surgery for an inguinal hernia (a hernia in the groin). In the SC group, a surgical intervention was performed in one child with a transposition of the great arteries and in another child with bilateral cryptorchidism.

One or more minor malformations were recorded in 24 PGD/PGS children, 23 ICSI children and 13 SC children. Skin anomalies (moles or spots and various birth marks) were the most frequently observed minor malformations in 18 ICSI children (25.7%), 14 PGD/PGS children (20%) and 10 SC children (14.3%).

In addition, the researchers excluded twins from the study because of the impact twin pregnancies can have on premature births, low birth weight, growth and malformations. "Further research on the outcome of PGD and PGS twins compared to ICSI and SC twins is mandatory," concluded Prof Bonduelle.

European Society for Human Reproduction and Embryology