Pregnancy
Questions Received:
Responses:
How long does it take to get back to your normal weight after having a baby? I had a baby 3 months ago. I put a lot of weight on because I gave up smoking when I was pregnant and I ate a lot instead of smoking. Also what is the ideal weight for a 24 year old medium frame, and about 5 foot 9 inches, female?
24th May 1999
Well done for giving up smoking in pregnancy. You certainly gave your baby the best start in life.
Smoking can stimulate the output of saliva, lessen hunger pangs for as much as an hour, reduce the secretion of gastric juice in the stomach and sometimes delay the emptying of the stomach. Therefore along with not knowing what to do with your hands and mouth it is understandable why so many people put on weight when they give up smoking.
Most people return to their normal weight by 12 months after having had a baby. There are many factors which will influence the rate of weight loss, for example: the amount of exercise taken, the quantity and type of food consumed and how you feed your baby.
Weight gain in pregnancy is usually 12 - 16 kg. If you are breastfeeding your baby you will start to burn off the fat laid down on your stomach and thighs at six months after delivery. If you are not breastfeeding it can take a lot longer, as much as a year longer and then only with exercise.
The average weight for a woman of medium frame, 5 feet 9 inches tall aged 24 is between 63 - 70 kg. but weight up to 76 kg. is acceptable.
We are grateful to Elizabeth Trevelyan, Senior Midwife at Heavitree Hospital, Exeter, for this response.
Could you please tell me if there is any way of finding out your pregnant before your period is due. I have a feeling I may be but I’m not sure if I should slow down in my aerobics classes and stop drinking alcohol. Thank you.
29th June 1999
A urine test is possible before your next period is due, but the result may not be reliable. The urine test is for the presence or absence of human chorionic gonadotrophin (HCG). "Chorionic gonadotrophin can be detected in the maternal plasma by radioimmunoassay as early as 6 days after fertilisation of the ovum, and is found in the urine soon after that. It reaches peak concentrations in the blood and urine at 10-11weeks gestation." (Lewis and Chamberlain, 1990)
Reference
Lewis, T.L.T., and Chamberlain, G.V.P. (editors) (1990) Obstetrics by ten teachers (15th edition). London: Edward Arnold (pp 12-13: Ovulation and early development of the ovum).
We wish to thank Susan Moore, Senior Lecturer in Midwifery at the University of Plymouth for her help with this question.
Why isn't an implanted embryo rejected by the mother in the way that an allograft is?
4th January 2000
The baby possesses genes from both parents, and is
therefore genetically different from her or his mother. This means that there is
the potential for rejection of the baby's tissues by the mother during pregnancy
if her immune system becomes activated against them, just as she would react to
other allografts. But most pregnancies progress without evidence of a rejection
process. If we knew how the baby achieved this, then organ transplantation and
the transfer of other genetically different grafts would become easier to
achieve.
There is no definitive answer yet as to why the conceptus is tolerated by the
mother, although several explanations have been suggested:
Perhaps the mother's immune system is 'turned down' or suppressed during pregnancy? However, the mother is able to fight infections successfully during pregnancy and will reject allografts in the same way as she would when not pregnant, so there is no evidence of a general immunosuppression during pregnancy
Then perhaps the uterus - or at least the endometrium - is an immunologically priviledged site? Perhaps here the immune system does not function in the way it does in most other parts of the body? (We know that within the eyeball, for example, allografts can survive without a rejection response being induced, so immunologically priviledged sites do exist.) However, there are at least two reasons why this explanation cannot be applied to the uterus: a graft of genetically-different tissue (for example of skin from another individual) made onto the endometrium will be rejected in the usual way, and conversely, if the conceptus comes into contact with maternal tissues other than the endometrium it is able to implant without rejection and support the pregnancy for a period of time, as seen in the case of ectopic pregnancies (implantation outside the normal uterine site). Thus it seems that the ability to avoid a rejection response resides with the trophoblast rather than the endometrium
Well, in that case perhaps the trophoblast is able to disguise its 'otherness'? Does it delete, or not make, or perhaps modify those molecular markers (antigens) that are usually involved in immune recognition? There is indeed evidence that trophoblastic tissues do not express key marker proteins known as major histocompatibility antigens that most other cells carry - including fetal cells - so that may reduce the risk of detection by the maternal immune system and rejection. Also, the surface of the syncytiotrophoblast that is in contact with the maternal blood becomes coated with fibrinoid, a fibrous material which might prevent immune cells from the mother's blood coming into direct contact with fetal tissues - a form of disguise.
So there is something special about the trophoblast that enables it to lie next to maternal cells and interact with them without triggering a rejection response. Generally, there is no mixing of cells between the maternal and fetal blood streams. If for some reason, though, a few fetal blood cells leak into the maternal bloodstream, then the mother will indeed begin to produce antibodies against her baby's blood, so the diplomatic immunity enjoyed by the trophoblast tissue is not shared by other fetal tissues.
I am 32 weeks pregnant with twins. At my appointment yesterday, my doctor said that there is some calcification of my placentas. He lead me to believe that this may lead to him performing a c-section prior to my expected due date. I wish to prolong this pregnancy at least 3 more weeks, to give the twins more valuable time to grow. Is there anything I can do to reverse, or stall the calcification process? Also how serious can this calcification affect my twins?
13 January 2001
Calcification within the placenta is quite a common finding - many people consider it to be a normal part of the maturation and aging of this organ in response to the increasing stresses placed upon it by the rapidly growing baby. The pattern of calcification (precipitation of calcium hydroxyapatite) is similar to that seen in other aging tissues, and is probably a response to cell death and diminished blood circulation in localised regions of the placenta.
One significant risk factor for placental calcification has been identified - smoking. Extensive calcification occurs more often in smokers than in non-smokers. Klesges et al (1998) confirmed a pathologic relation between smoking and placental calcification and suggested that the dietary antioxidants vitamin C, vitamin E, and beta-carotene may help to reduce villus calcification in smokers.
Realistically, though, it is unlikely that any actions at this stage in your pregnancy other than those common-sense ones which which maintain good physical and mental health will significantly change the calcification process. Your doctor will be able to advise you on the progress of your pregnancy, and will continue to monitor any changes in the degree of calcification and any possible effects on your twins.
Reference
Klesges, L.M., Murray, D.M., Brown, J.E., Cliver, S.P. and Goldenberg, R.L. (1998) Relations of cigarette smoking and dietary antioxidants with placental calcification. American Journal of Epidemiology, 147, 127-135.