It has led them to warn that couples undergoing IVF, in which the woman has healthy fallopian tubes and the man has normal semen parameters, should be cautioned against having unprotected intercourse once the initial few days of ovarian stimulation by drugs has passed.
Dr Amin Milki of the Department of Gynaecology and Obstetrics at Stanford University in California, said that the woman had two five-day embryos transferred to her womb after egg retrieval and test-tube fertilisation. But, a scan at seven weeks showed quads and she gave birth by caesarean section at 32 weeks to a boy and a girl with separate placentas and two girls with fused placentas. DNA tests showed that the boy and one girl were fraternal twins and the other two girls were identical twins. Tests on the placentas, together with the DNA evidence, suggested that the identical twins were derived from a single fertilised egg in which division had occurred before implantation.
"It would appear that the two transferred embryos led to fraternal twins, and a spontaneous conception with the embryo splitting in-vivo by day 4 resulted in identical twins. The couple had admitted having intercourse five days prior to the retrieval of eggs for IVF," said Dr Milki. "It is just possible that the identical twins could have resulted from one of the transferred embryos splitting. But even if that were true at least one foetus would have been conceived spontaneously. That is incontestable based on the genetic testing."
He said that multiple pregnancies were medically undesirable for any patient and especially for those unwilling to undergo foetal reduction. "It may be prudent to caution IVF patients with no tubal or semen abnormalities against unprotected intercourse once the early days of ovarian hyperstimulation are over, especially if they will not consider foetal reduction in the event of a multiple pregnancy."
* Concurrent IVF and spontaneous conception resulting in a quadruplet pregnancy. Human Reproduction Vol. 16. No. 11. pp 2324-2326. A.A. Milki, M.D.Hinckley, F.C. Grumet, U.Chitkara. Dept of Gynecology & Obstetrics and Dept of Pathology, Stanford University, California.
Human Reproduction