When a Twin is not a Twin

Sep 28, 2009 by Lin Edwards weblog

(PhysOrg.com) -- A woman in Fort Worth, Arkansas is carrying two babies that may not be twins, and which may have been conceived two and a half weeks apart. The two babies may be the result of superfetation, a rare phenomenon in which the woman ovulates and conceives again while already pregnant.

Mrs Julia Grovenburg knew she was pregnant with a girl (named Jillian), but while examining her, doctors also found a smaller baby growing alongside the girl. The younger baby is believed to be a boy, and has been named Hudson.

The Grovenburg's physician, Dr M. Muyalert confirmed in a statement that Julia is carrying two , but that there was a big difference in size of the two fetuses, which the doctor said is possibly due to superfetation.

Superfetation is extremely rare, but the second conception can occur up to 24 days after the first according to Karen Boyle, a fertility expert at the Greater Baltimore Medical Center, speaking on ABC TV. When that happens the second baby can have problems in lung development. The gap between the Grovenburg's first and second babies is probably short enough to minimize health concerns.

Duke University Medical Center's professor of and , Dr Jeffrey Kuller, told WebMD he is skeptical, but it is possibly a case of superfetation. The phenomenon is so rare there have been only a "handful" of cases in the literature. The hormonal changes in normally prevent ovulation, but it is possible.

Another explanation for the discrepancy in size is that one of the twins has a chromosomal defect or other medical problem that stunts its growth, but such a large discrepancy in size is unlikely. If the second baby was much smaller its presence may have been missed in the early examination that located the first baby, Dr Kuller said.

The main issue facing Julia and Todd Grovenburg is the timing of the delivery, which would have to be a compromise that is best for both of the babies. In an interview on an Arkansas TV station (KFSM), Julia Grovenburg said the babies both appeared to be healthy, and will probably be delivered in December. Metabolic and chromosomal studies of the babies after they are born should be able to confirm if the pregnancy is a case of superfetation.

Two confirmed cases of superfetation occurred in 2007 when Lia and Ame Herrity were born in Scotland, and Thomas and Harriet Mullineux were born in Essex. Both cases were pairs of babies conceived three weeks apart.

© 2009 PhysOrg.com

Explore further: Key element of CPR missing from guidelines

add to favorites email to friend print save as pdf

Related Stories

Late preterm births present serious risks to newborns

Dec 11, 2008

More than half a million babies are born preterm in the United States each year, and preterm births are on the rise. Late preterm births, or births that occur between 34 and 36 weeks (approximately 4 to 6 weeks before the ...

Recommended for you

Key element of CPR missing from guidelines

19 hours ago

Removing the head tilt/chin lift component of rescue breaths from the latest cardiopulmonary resuscitation (CPR) guidelines could be a mistake, according to Queen's University professor Anthony Ho.

Burnout impacts transplant surgeons (w/ Video)

Jul 28, 2014

Despite saving thousands of lives yearly, nearly half of organ transplant surgeons report a low sense of personal accomplishment and 40% feel emotionally exhausted, according to a new national study on transplant surgeon ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

Birthmark
3 / 5 (1) Sep 28, 2009
Interesting, had no idea this could happen. I wonder if someone has had "twins", whom was not available, like some, to technologies that we have so conveniently or in this time period, and they went on believing they were twins.