Pregnancy Glossary

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• C-section; Caesarean - Abdominal operation used to surgically remove the baby from the mother. Used mainly in cases where the baby is not fitting, or the mother and /or baby is having a nonreassuring situation.

• cerclage - A pursestring stitch that is placed in the cervix of a pregnant patient that has a specific problem with her cervix called cervical incompetence. In these patients the cervix is weak and pressure caused by the developing pregnancy can cause the cervix to open and the baby can be lost without this stitch. It is a very brief procedure that is done with either epidural or a light general anesthetic. In patients with known cervical incompetence it is done prophylactically (preventatively) between 12 and 14 weeks. It can be done even later as a rescue or emergency cerclage in patients who come in with bleeding or cervical shortening in the absence of preterm labor. These cerclages can even be done at 20 or 22 weeks. The risk of a cerclage is accidentally breaking the bag of water, bleeding, or infection.

• cervical incompetence - A cervix that is inherently weak and painlessly dilates in the midtrimester followed by breaking of the water and loss of the baby. It can be caused by prior cervical surgery such as LEEP or cone biopsies, multiple abortions (especially later gestation terminations), DES exposure to the mother in utero, or just inherently poor cervical tissue for no reason (this is the most common cause). Once you diagnose this, if the water has not broken you can put in a cervical cerclage (stitch), or if the patient has lost a prior pregnancy to this condition, you can preventatively place one at 12-14 weeks in the next pregnancy.

• cervix - Opening into the uterus. During childbirth, the cervix dilates (opens), allowing the baby to move from the uterus through the cervix and then through the vagina.

• Choironic villus sampling (CVS) - A test done at 11-13 weeks of pregnancy to determine if the fetus has normal chromosomes. Can diagnose a chromosomally abnormal baby earlier than an amnioscentesis (done at 15-18 weeks and you get results in 10-14 days). CVS results are back in just a few days and if the fetus is chromosomally abnormal, the mother can have an earlier termination of pregnancy if that is what she chooses. A small sample of chorionic villi (placental tissue) is obtained with a needle placed either in the abdomen or through the vagina and evaluated for chromosomes. The down side is that there is a higher pregnancy loss rate with CVS over amnio (1/100 versus 1/200-400), and the test requires specialized training (usually maternal fetal medicine specialists perform CVS, whereas amnio is done by almost all general ob/gyns). There was a prior concern that there may be more limb reduction defects with CVS, but this was disproved. CVS does not test for neural tube defects (spinal birth defects), whereas amnio tests for both chromosomes and NTDs. A separate blood AFP test will need to be done at 15-18 weeks to test for NTDs in those patients who had CVS.

• Contractions - tightening of the muscular uterus. The pregnant uterus normally contracts 3-4 times an hour and patients don't even realize this. Braxton hicks contractions are practice contractions that occur most commonly in the last four weeks of pregnancy. They can occur much earlier with subsequent pregnancies, but they don't cause the cervix to dilate. Real contractions of the uterus are painful and start in the back and radiate to the front, and once they start occurring every five minutes lasting sixty seconds, for an hour they cause cervical change (dilation). Contractions are a necessary part of the laboring process and cause the cervix to open progressively until it reaches the required 10 cm of dilation.

• Crowning - A term used to describe the fetal head coming over the vaginal skin at the time of delivery. It is used to describe the moment before the head actually comes out of the vagina.

• Dilation - Describes how much the cervix is opened during pregnancy. It is measured in centimeters, and full dilation is 10cm. To deliver a full term baby the cervix must be opened 10cm to allow the fetal head enough room to pass. The widest diameter of a fetal head is about 10cm.

• Down syndrome - A chromosomal abnormality in a fetus where there is an extra 21st chromosome. Humans have 46 chromosomes, 23 from their mother (the egg) and 23 from their father (the sperm). Babies with Down syndrome have an extra chromosome 21 ( three instead of 2 because in the process of forming either the sperm or the egg when the 46 chromosomes pulled apart to put 23 in each sperm or egg, chromosome 21 didn't pull apart correctly and both copies went into one sperm or egg, giving it 24 chromosomes). When this sperm or egg met another egg or sperm to form an embryo it then had 47 chromosomes instead of 46. This leads to mental retardation, and these babies can also have heart defects and other problems.