Pregnancy is measured in three time periods, or trimesters, starting with the first day of the last menstrual period. During each trimester, specific fetal developments occur and the full term pregnancy is considered 40 weeks.
The information contained below is for general patient education. Ask your OB/Gyn about specific developmental milestones and symptoms you experience in each trimester.
The First Trimester (0-13 weeks)
Maternal changes during the first trimester include:
The Second Trimester (14-26 weeks)
Maternal changes during the second trimester include:
The Third Trimester (27-40 weeks)
Maternal changes during the second trimester include:
Choosing the person who will deliver your child is a personal decision and there are various types of healthcare workers who can be involved in your delivery. Listed in this patient education guide are the doctors most commonly called on by expecting mothers.
Our pregnancy education guide gives you an overview of what you can expect and how to prepare in each of the trimesters throughout your pregnancy.
How to Prepare for the First Trimester
During the first trimester, preparation focuses on getting you ready to give birth in nine months.
How to Prepare for the Second Trimester
During the second trimester, preparation focuses on the birth and future care of the baby.
How to Prepare for the Third Trimester
As one approaches the home stretch, preparation centers on the actual delivery event and post-delivery actions.
From that first moment when you realize you're pregnant up until your delivery, you will have questions about your pregnancy.
Below is a list of helpful questions for each trimester of your pregnancy.
Question About My Diagnosis
Questions About My Lifestyle & Family
Question About My Diagnosis
Questions About My Lifestyle & Family
Question About My Diagnosis
Questions About My Lifestyle & Family
During each obstetrical visit throughout the pregnancy, the medical assistant or nurse will measure weight and blood pressure while sitting. The urine is also tested each time for glucose, protein and blood.
The fundal height, or height of the uterus, is measured from the top of the pubic bone to the top of the uterus. At 20 weeks the fundal height will reach the level of the umbilicus and from then until 35 weeks, there is a consistent relationship between the pregnancy length and fundal height (exceptions include multiple gestation i.e. twins or fibroids). Read more about common tests in this patient education guide.
Common Tests in the First Trimester
| Test | Why Test? | What Happens? | Normal Result |
|---|---|---|---|
|
Blood Type and Rh |
If Rh Negative, will test Father for Rh to ensure compatibility with baby |
After a tourniquet is applied to the upper arm, the puncture site of skin is swabbed with alcohol and a needle punctures the skin, entering a vein. Blood is drawn into a syringe for analysis. The tourniquet is then removed and a pressure bandage is applied |
Rh Positive is less risk |
|
Complete Blood Count |
Checks for anemia |
After a tourniquet is applied to the upper arm, the puncture site of skin is swabbed with alcohol and a needle punctures the skin, entering a vein. Blood is drawn into a syringe for analysis. The tourniquet is then removed and a pressure bandage is applied |
WBC=4.5-11 RBC=4.1-5.1 Hemoglobin Female= 12-16 Hematocrit Female=36-46% |
|
Screen for Rubella,hepatitis B, syphilis and HIV |
Checks for immunity |
After a tourniquet is applied to the upper arm, the puncture site of skin is swabbed with alcohol and a needle punctures the skin, entering a vein. Blood is drawn into a syringe for analysis. The tourniquet is then removed and a pressure bandage is applied |
IgG antibodies <7IU/mL HIV negative, hep.neg. VDRL negative |
|
Tay-Sachs |
Checks for risk of the disease |
After a tourniquet is applied to the upper arm, the puncture site of skin is swabbed with alcohol and a needle punctures the skin, entering a vein. Blood is drawn into a syringe for analysis. The tourniquet is then removed and a pressure bandage is applied |
Hexosaminidase A: 7.2-9.8 U/L Total Hexosaminidase= 9.8-15.9 U/L |
|
Sickle Cell Anemia |
Checks for risk of the disease |
After a tourniquet is applied to the upper arm, the puncture site of skin is swabbed with alcohol and a needle punctures the skin, entering a vein. Blood is drawn into a syringe for analysis. The tourniquet is then removed and a pressure bandage is applied |
Hemoglobin A (not S) |
|
Ultrasound |
Confirms age of fetus Visualizes structural abnormalities in uterus and fetus |
After lying down on the table, the technician/doctor places clear water-based gel on your tummy and pelvic area. A hand-held probe is then moved back and forth over the area, transmitting sound waves. The echoes of these waves creates an image on a computer monitor Sometimes a transvaginal ultrasound is performed. Here, you lie on the exam table with knees bent and feet in stirrups. A covered probe is lubricated and placed in the vagina. The probe emits sound waves and the echoes create an image on a computer monitor. |
Fetal and uterine size matches the date No structural problems seen |
|
Urine |
Presence of glucose, protein, blood |
Urine is placed in a cup for analysis. The technician dips a special paper into the urine for analysis with color changes |
Glucose, protein and blood should be absent in a normal specimen |
|
Chorionic Villus Sampling |
Screens baby for genetic defects at 10-12 weeks |
An ultrasound locates the uterine position and placental position in the uterus. The vulva, vagina cervix and abdomen are wiped with an antiseptic wash. A thin plastic tube is inserted through the vagina and cervix to reach the placenta, guided with ultrasound and a small sample of tissue is removed. In the transabdominal approach, a needle is inserted through the abdomen and uterus into the placenta. Tissue is withdrawn into a syringe |
The DNA of the baby is analyzed. It fails to detect neural tube defect or Rh incompatibility and an amniocentesis is needed if this is a concern. A normal test means there are no genetic defects. |
Common Tests in the Second Trimester
| Test | Why Test? | What Happens? | Normal Result |
|---|---|---|---|
|
Blood for genetic markers (done in 15-18th wk): |
Abnormal markers indicate the need for additional testing (usually a sonogram and possibly an amnio-centesis) Abnormal levels suggest:
Abnormal levels are linked to increased risk of chromosomal abnormality |
After a tourniquet is applied to the upper arm, the puncture site of skin is swabbed with alcohol and a needle punctures the skin, entering a vein. Blood is drawn into a syringe for analysis. The tourniquet is then removed and a pressure bandage is applied |
Alpha-Fetoprotein Screening (AFP) Normal range is .5-2.0 or 2.t MoM Human Chorionic Gonadotropin (hCG) The hCG levels increase during the pregnancy At 13-16 wks=13,300- 254,000 mIU/ml 17-24 wks=4,060- 165,400 mIU/ml Estriol & Inhibin Estriol and inhibin is elevated more than twice the median value in normal pregnancies with genetic problems |
|
Amniocentesis |
Done during the 16-18th gestational week to do the following:
|
The doctor inserts a needle through the abdomen and into the uterine sac to remove a small amount of amniotic fluid. The needle is withdrawn and pressure is applied to the puncture site The test is usually done with ultrasound guidance to locate the amniotic fluid. |
XX for girl XY for boy Hexosaminidase A is absent |
|
Urine Test |
Looks for glucose, protein and blood in the urine |
Urine is deposited into a cup. The technician then dips a special paper into the urine which changes color for presence of these three substances. |
Normal result is when these are absent |
|
One-Hour Glucose Tolerance Test |
Rules out Diabetes |
You are given a cup of a 50 gm. sugar solution (orange or cola flavored) to drink. After one hour, blood is drawn and analyzed for sugar level. |
Less than 140 mg/dL is normal. |
Common Tests in the Third Trimester
| Test | Why Test? | What Happens? | Normal Result |
|---|---|---|---|
|
Group B Streptococcus Screening |
B Strep is associated with
|
Swabs of the vagina and rectum are taken at 35-37 weeks to screen for presence of group B strep. |
Negative presence of bacteria |
|
Non-Stress Test |
Indicated in high-risk pregnancies as:
|
Fetal monitor is strapped across the mother's abdomen with the device over the region of the fetal heart and a tracing is obtained of the fetal heart rate over time. Takes about 20 min. |
Normal fetal heart rate is 120-140 beats/minute. Dips (decelerations) or accelerations beyond 140 is not seen |
|
Contraction Stress Test |
Predicts how the baby will cope to labor stress |
The fetal monitor is strapped across the mother's abdomen. She is then asked to stimulate the nipples to stimulate contractions or pitocin is given intravenously to create contractions. The fetal heart rate is then measured in response to the contractions. |
Normal fetal heart rate is 120-140 beats/minute. Dips (decelerations) or accelerations beyond 140 is not seen When decelerations are seen in conjunction to the time of the contractions, it can suggest fetal head compressions. |
|
Biophysical Profile |
Gives a more accurate assessment of baby wellness |
Most often done between 38-42 wks of pregnancy. Combines a non-stress test with an ultrasound |
Rating of 0-2 (with 2 normal) is given for each of the following, with a score of ten as the best:
A total score under 6 is abnormal and calls for delivery. |
|
Electronic Fetal Heart Monitoring |
Tests fetal heart rate |
A fetal doppler is placed on the mother's abdomen over the fetal heart site |
Regular pattern with 120-140 beats/min. |
|
Pelvic Digital Examination |
Assess any dilatation or thinning of the cervix and where the position of the fetal head is located in conjunction to the birth canal. Performed during the last 4 weeks of pregnancy |
The patient bends her knees with her legs abducted and feet on the bed or in "frog-leg" position. The examiner gently parts the vaginal labia and inserts two fingers into the vagina and palpates the cervix to assess effacement (thinning of the cervix) and dilatation, estimated by the number of fingers that would span the opening. (For example, when the cervix is 3-4 cm dilated, 2-3 fingers would span the opening. When 10 cm. occurs, the opening is equivalent to five fingers.) |
Effacement is the thinning out of the cervix in labor which goes from uneffaced at 0% to 100% effaced in normal labor. Dilatation goes from closed to 10 centimeters in normal labor |
When it comes to delivery, there are many different variables that can effect the birth. Some methods and treatments are optional, and some will become a necessity as your labor progresses. Read more in this patient education guide.
Delivery Methods
| Delivery method | How it Works |
|---|---|
|
Induction |
Occasionally an enema is all that is needed to stimulate labor. More commonly evoked by IV infusion of pitocin to bring on regular contractions. After labor has commenced, an internal electrode may be inserted on the fetal head for a more accurate reading by rupturing membranes. |
|
Episiotomy |
Incision through vaginal wall and perineum, made when:
After delivery the incision is sutured (which heals better than a ragged tear that needs sewing) |
|
Spontaneous |
Natural labor with rhythmic contractions and progression of the baby through the birth canal and delivered without instruments or prompting. |
|
Forceps |
Metal instrument with tongs and spoon-shaped edges molded to fit around the baby's head. Forceps are used to:
|
|
Vacuum Extraction |
Device with cone-shaped synthetic, pliable suction cup which is placed over the baby's head and attached to a pump, creating vacuum which has measured pressure applied. This enables the physician to hold the baby in place with each push, barring the baby from receding between contractions. |
|
Caesarean Section |
This is an operative delivery with an incision (either horizontal or vertical) made between the umbilicus and pubic bone, and carried down to the uterus, which is incised above the lower uterine segment. The baby is delivered within 5 minutes and the placenta is then manually removed. The remainder of the 45-60 minutes entails sewing the various layers to restore normal tissue integrity. Indications include:
|
Anesthesia Options
There are two reasons why one would opt for anesthesia to be given.
In the first scenario, a patient may not be knowledgeable in deep breathing or natural birthing techniques that lessen pain or the patient may find it inadequate for the amount of pain that she is perceiving.
In the second case, anesthesia techniques are induced in order to relax the patient and the muscles so that delivery may be more easily affected.
| Type | How it Works |
|---|---|
|
Local Anesthetic |
Medication injected subcutaneously to numb a specific area prior to episiotomy or for mending a tissue tear in the perineum. It does not alter contraction pain. |
|
Cervical Block |
Local anesthetic injected into the cervix at four quadrants to lessen the pain associated with dilation and effacement of the cervix. |
|
Pudendal Block |
Local anesthetic is injected into the vaginal wall to numb the tissue between vagina and anus. Given in advanced labor and is effective in 10-20 minutes |
|
Epidural Block |
After lying or sitting on your side with back curved outward, a local anesthetic is injected to numb the lower back at the site of planned epidural needle entry. Medication is injected into the epidural space surrounding the spinal cord and becomes effective in 10 minutes. Sensory function is numbed while often retaining motor skills. |
|
Spinal Block |
Used in conjunction with instrument delivery. You sit or lie on your side and medication is injected with a spinal needle into the sac of fluid below the spinal cord, effective within minutes. |
|
General Anesthesia (inhalation gases) |
Administered by the anesthesiologist, this is a gas that is passed through a special machine and dosage regulated. Because it can sedate the baby, this is given when immediate sedation is needed as in imminent Caesarean section for fetal distress. |
Written by Barbara Hales, M.D.
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