••• Chapter 3^ Physiology of Normal Pregnancy^27
❍ What is considered to be the main functional cell of the placenta and from what does it derive?
The syncytiotrophoblast is the major site of hormone and protein production. It is derived from the
cytotrophoblast.
❍ What is the term for the normal eversion of the endocervical glands out to the ectocervix during pregnancy?
Ectropion.
❍ What are the changes in cervical mucous that occur in pregnancy?
Thick tenacious mucous forms a plug blocking the cervical canal, thus preventing ascending infection (important
in evaluating patients for pelvic inflammatory disease).
❍ What percentage of sodium chloride is necessary in the cervical mucous to develop a full ferning
(arborization) pattern when dried on a slide?
1%.
❍ What pattern is most likely seen on a slide of dried cervical mucous during pregnancy?
Fragmentary crystallization or beading typical of the effect of progesterone-sodium chloride concentration that is
usually <1% during pregnancy.
❍ Does the strength of the cervix decrease during pregnancy?
Yes. Collagen is rearranged to produce a 12-fold reduction in mechanical strength.
❍ Describe the changes in vaginal secretions in pregnancy.
Increased cervical and vaginal secretions result in thick, white odorless discharge. The pH is between 3.5 and
6.0 resulting from increased production of lactic acid from the action of Lactobacillus acidophilus.
❍ What is the proposed mechanism for the increased pigmentation of skin found in pregnancy? Give two
examples.
Melanocyte-stimulating hormone (MSH) is elevated from the end of the second month of pregnancy to term.
Estrogen and progesterone may have melanocyte-stimulating properties. Estrogen and progesterone may also
stimulate the hypertrophy of the intermediate lobe of the pituitary which is where MSH and b-endorphin
are formed from the metabolism of proopiomelanocortin. Two examples are the linea nigra and the melasma
gravidarum.
❍ What are the glands of Montgomery?
Normal finding of hypertrophic sebaceous glands scattered throughout the areola of a pregnant woman’s breast.
❍ What is the average weight gain in pregnancy?
11 kg (25 lbs).
❍ What percentage of maternal weight gain is contributed by the fetus and placenta at term?
Approximately 30%.