Re: velamentous cord ins
From: James S Smeltzer MD (gaperina@mindspring.com)
Mon Mar 1 13:04:29 1999
Terry,
I agree with that formulation. I have many examples of Previa that have
resolved with fibrosis & infarction of the previa portion. We are certain
that the placenta initially completely surrounds the gestational sac, but
very few do at the end. We know that at the same time, it grows early in
pregnancy andtakes up more of the uterine surface.
The velamentous insertion may be present initially if the chorion laevae
(poor trophic effect) is on the side of the fetal pole in the blastocyst->
developing trophoblast. I have seen a velamentous insertion around old
infarcted cotyledons, that were at the cervical os. [Pearl of the day: If
the membranes feel any way other than perfectly smooth, look before you
hook!]. JSS
At 12:38 PM 2/26/1999 -0600, you wrote:
>Hi, Terry
>Second question first. There was an article by Jauniaux, et al in
>Obstetrics & Gynecology in 1990: Pathologic features of placentas from
>singleton pregnancies obtained by in vitro fertilization and embryo
>transfer.
>
>As for placental migration, I'm kind of taken with the theory of
>trophotropism, which says that placental tissue tends to proliferate in
>the more vascular areas of the uterus and will diminish/atrophy in
>less-abundantly supplied regions like the lower segment. But I don't
>have any hard data to support it.
>
>Regards, Paula
>
>At Fri, 26 Feb 1999, DuBose, Terry wrote:
>>
>>Paula & Patricia, I too have an interest in placenta, cord insertions, and
>>placental "migration".
>>
>>Paula, you seem to have a bit of experience in this. Could you share you
>>feelings concerning placental migration? In your opinion do you believe
>>that placenta movement away from the internal os is more due to uterine wall
>>growth or placental growth away from the os and atrophy nearer the os
>>(resulting in velamentous membranes)? Also, do you have a reference for the
>>eccentric cords in IVF patients that you mentioned?
>>
>>Patricia, I followed a case of discordant twins from 6 weeks to term once,
>>got full medical reports on delivery and followed the babies out to 3 years
>>of age. This is case is reported in FETAL SONOGRAPHY, W. B. Saunders Co.,
>>1996, p. 153-154. Briefly, the twins were discordant by approximately 1
>>week at 5.9 weeks LMP. Each twin's EHR was appropriate for the respective
>>CRL. That is the larger twin had the higher EHR until the peak at 9.2 weeks,
>>at which time the larger twin's EHR started to decelerate first. (see:
>>http://www.obgyn.net/ENGLISH/PUBS/FEATURES/dubose/ehr-age.htm) The
>>discordant growth remained constant (1 week difference) until approximately
>>26 weeks, when the discordance started to increase. They spontaneously
>>delivered at 34 weeks. Both survived (A 2700 g, APGAR 8 & 9) (B 1955 g,
>>APGAR 7 & 9). The placental path indicated some venous channels from side
>>"A" across the membranous partition into side "B". In addition cord B was a
>>velamentous insertion and the cord diameter was approximately one half that
>>of cord A. For a complete discussion see the above reference (FETAL
>>SONOGRAPHY).
>>
>>Thanks for your discussion.
>>
>>Peace, Terry J. DuBose, M.S., RDMS, FAIUM
>>University of Arkansas for Medical Sciences, USA
>>Director, Diagnostic Sonography Program
>>http://www.uams.edu/chrp/dmshome.htm <http://www.uams.edu/chrp/dmshome.htm>
>>VOICE: 501-686-6510 FAX: 501-686-6513
>>Chair, http://www.obgyn.net/us/us.htm <http://www.obgyn.net/us/us.htm>
>>http://www.io.com/~dubose/ <http://www.io.com/~dubose/>
>>Now is the time for all good folks to come to the aid of the Earth.
>>----
>>
>> -----Original Message-----
>> From: woletzps@umdnj.edu [SMTP:woletzps@umdnj.edu]
>> Sent: Friday, February 26, 1999 11:13 AM
>> To: Multiple recipients of list
>> Subject: Re: velamentous cord ins
>>
>> Hi, Patricia
>>
>> While we've never written it into our protocol, we do routinely look
>>for placental cord insertions when there is a growth discrepancy between
>>twins. Velamentous cord insertion can also account for small-for-dates
>>singletons, and, of course, the greatest concern regarding velamentous
>>insertion is when the vessels cross the internal os, creating vasa previa.
>>
>> Here's a bit of placenta/cord trivia for you: IVF pregnancies have a
>>higher rate of eccentric cord insertions than do spontaneous conceptions.
>>
>> (One of the things I love about this field is that there's always
>>more to learn!)
>>
>> Regards,
>> Paula
>
>--
>Paula S. Woletz, MPH, RDMS, RDCS
>University of Medicine and Dentistry of New Jersey/
>St. Peter's University Hospital
>New Brunswick, NJ
>woletzps@umdnj.edu
>
