Common Terms and Abbreviations Used in Obstetrics

LMP = Last Menstrual Period.
Use the first day of the last menstrual period to calculate the due date. The quick way to do it in your head is to count backwards 3 months from the first day of the LMP, then add 7 days. So if the LMP was 8/15, the 3 months backwards is 5 (May) plus 7 days added to the 15th=22, so the due date is May 22.

EDC or EDD = the due date.
EDC stands for the old-fashioned “estimated date of confinement.” EDD is the more modern “Estimated Day of Delivery.” The key word here is “estimated.” Babies take different lengths of time to get “done,” and anywhere from 3 weeks before to 2 weeks after the due date the delivery is “at term.”

Trimester = the pregnancy is divided into 3 “trimesters.”
The first one is from LMP up until 12 or 13 weeks.
The second trimester is from 12-13 weeks until 28 weeks.
The third trimester is from 28 weeks until delivery.

NSVD = normal spontaneous vaginal delivery

SVD = spontaneous vaginal delivery – same as NSVD

VAD = vacuum assisted delivery.
The doctor (not us midwives) applies a suction cup (like a plumber’s helper) to the baby’s head and gently draws it out, when the mother is too tired to push effectively any more but the baby is very low in the pelvis.

Primary Cesarean Section = first time a mother has delivered by Cesarean. (*1E)

Secondary Cesarean Section = mother has already had a previous Cesarean delivery, and this is a repeat Cesarean birth. (*2E)

VBAC = Vaginal Birth After Cesarean.
The mother has had a previous Cesarean delivery but has now delivered vaginally. There is a small amount of risk (less than 1%) that the old surgical scar on the uterus will rupture when a VBAC is attempted, so mothers who wish to attempt a VBAC must understand the risks and sign an “informed consent” that shows they are aware of the risks/benefits.

TOL = Trial of Labor.
If a woman has had a previous Cesarean birth and wants to have a VBAC, she is said to be undergoing a “trial of labor” when her contractions start.

ME = median or midline episiotomy.
A cut made with surgical scissors from the opening of the vagina straight back toward the rectum just before the birth. We would do one of these if it seemed the woman was going to tear in an area where it is hard to do a repair, like up by the clitoris, or if the baby’s heartbeat is low and we cannot wait for the tissue to stretch naturally, to get the baby out sooner.

MLE = mediolateral episiotomy.
The cut is made from the vaginal opening at an angle more toward the leg than straight back. Elizabeth and I don’t do these.

Perineal laceration = a natural tearing of the tissue between the vaginal opening and the rectum.
It used to be taught that it was better to cut an episiotomy than allow a tear, but in the last 25 years all the research in OB literature has shown that lacerations are usually not as large as episiotomies, heal faster than episiotomies, and are less painful than episiotomies.
There are 4 “degrees” of lacerations:
A first degree laceration 1E is minor and does not involve muscle.
A second degree laceration 2E is equivalent to a median episiotomy, and does involve some muscle.
A third degree laceration 3E involves some of the muscle of the rectal sphincter, and a fourth degree laceration goes all the way through the rectal sphincter.

G = gravida.
The number of times the woman has been pregnant. Usually seen in association with:
P = the outcome of those pregnancies.
Examples:
G1P0 = the woman is pregnant for the first time and has not yet delivered
G1P1 = the woman has had one pregnancy and has delivered once
There can be 4 numbers after the “P” for “para.”
The first number is how many term pregnancies.
The second number is how many premature babies.
The third number is how many abortions or miscarriages
The fourth number is how many living children survive.
Examples:
G4P1111 = the woman is currently pregnant with her fourth pregnancy. She had one full-term delivery, one premature delivery which did not survive, one abortion or miscarriage, and has one living child.
G3P2002 = the woman is pregnant with her third child and has two living full-term kids
G6P2124 = the woman is pregnant with her sixth pregnancy. She had 2 abortions or miscarriages, and surviving children include 2 full-term pregnancies and one premie which survived. Since the last number indicates she has 4 living kids, then you have to figure that one of the pregnancies was a twin pregnancy and both the babies survived.

VTOP = Voluntary termination of pregnancy

SAB = spontaneous abortion

IVF = in vitro fertilization.
Egg(s) harvested from the mother are fertilized in the lab with the father’s or a donor’s sperm, when couples have been unable to conceive naturally. If a couple has had IVF, then we can calculate the due date from the date of conception rather than the date of LMP.

Sono, sonogram, ultrasound, scan = different terms for the same thing: looking at something inside the body by bouncing high-frequency sound waves off the internal structures to get a picture of what’s inside.

Dating scan = Most accurate in first trimester. Used to get an EDC when the LMP is unknown or the midwife finds that the uterus is smaller or larger than it should be, given the number of weeks from the LMP.

Nuchal translucency = sonogram at 11 – 13 weeks of gestation which measures the thickness of the fold of the neck on the back of the fetus. This can be quite difficult since the fetus is still very small at this point, and may be moving around a lot. However, if the neck fold is abnormally thickened it is very suspicious for a finding of Down Syndrome or another fetal abnormality. This sonogram is most often paired with a blood test called the Ultrascreen, First Screen, or etc. to calculate a “risk score” for Down Syndrome/associated anomalies. Remember, this is a SCREENING TEST ONLY. It cannot diagnose a problem, only point out that a problem MAY BE there. The mother must have a definitive test ( amnio or CVS) which actually examines the chromosomes of the fetus before anyone can say for sure that there is truly a problem with the baby.

Anatomy scan = done at about 20 weeks gestation (as measured from LMP).
A very comprehensive sonogram to look for any fetal anomalies. Can usually detect abnormalities in the brain, heart, bones (including spine) , facial features, kidneys, stomach, liver, genitals. Could not see an internal problem, like cleft palate. Cannot by itself rule out Down Syndrome, as the thickness of the neck fold which is apparent at 11 – 13 weeks has disappeared by this point in the pregnancy.

CVS = Chorionic villus sampling.
The “villi” (plural of villus) are parts of the placenta. Since the baby and the placenta form from the joining of the egg and the sperm, the genetics of the placenta is usually the same as the genetics of the placenta. So if a very small portion of the placenta is taken for analysis at 11 weeks or so from the LMP, it should be possible to be sure whether the placenta/baby are affected by Down Syndrome (or another problem). This procedure has a risk of miscarriage of 1 -2%. The most experienced center for CVS in Manhattan in Mt. Sinai Hospital, where we would refer any patients who are interested in this procedure.

Amno = amniocentesis.
Another procedure, which, like CVS, is 100% accurate in diagnosing genetic problems because it can obtain fetal tissue for analysis, but because it is an “invasive” procedure also incurs a risk of a 1-2% loss of the pregnancy. It is done around the 16 week from LMP, and involves a needle penetrating the uterine wall to obtain amniotic fluid. That amniotic fluid contains sloughed-off skin cells of the fetus, which can be examined under the electron microscope to look at the number of chromosomes. 3 copies of the 21st chromosome indicate Down Syndrome. Other trisomies exist but are much rarer.

GST = glucose screening test.
This is a SCREENING test only for diabetes of pregnancy, done at 26-28 weeks from LMP. If over 135, it indicates the patient needs a full 3 hour GTT (glucose tolerance test) for diabetes of pregancy, which is the definitive test.

GBS = Group B Strep.
This is an organism which is not a sexually-transmitted disorder, and which causes no problems for any woman who carries it or any man who might have intecourse with her. It is only a potential problem for a woman who is a carrier (as are about 20% of normal women) who is going to have a baby. If a woman is a carrier of this organism, she could potentially pass it on to her child during delivery, and the child could POSSIBILY become very sick. The Centers for Disease Control in the US has advised that all practitioners test every pregnant woman under their care for GBS at 34 – 37 weeks gestation, and treat all positive results with antibiotics in labor to prevent transmission to the infant. If the mother is positive for GBS, she can still deliver in the Birthing Center if she meets all other criteria, but she must have antibiotics before delivery or the pediatricians will insist on a longer hospital stay so they can make sure the baby is not affected adversely.

NST = Non-stress test.
Done to make sure the baby is healthy, usually in the third trimester of pregnancy; most often when the mother is a week or more overdue but also done if the mother reports decreased fetal movement. Involves putting an external fetal monitor on the mother’s abdomen to record fetal movements and to see that the baby’s heartbeat increases when the baby moves.

BPP= biophysical profile.
A type of sonogram done in the third trimester to assess the baby’s health.Doctor looks for baby’s movements, heart rate, etc. and especially the amount of amniotic fluid. If the amount of amniotic fluid is markedly decreased, they will often recommend we induce the patient.