Lecture Notes, Biology 203, Human Sexuality and Reproduction

Pregnancy and Childbirth, continued

  • Disorders of Pregnancy
    1. Hemorrhagic disorders (excessive bleeding)
      1. Spontaneous abortion (miscarriage)
        1. Causes: >50% fetal/placental origin, 15% maternal, rest cause unknown
        2. 3/4 of miscarriages happen before 16th week, most before the 8th week, possibly a large number very early before conception can be confirmed
        3. Bleeding, painful cramping (uterine contractions), loss of tissue
      2. Ectopic pregnancy (implantation and/or development outside uterus)
        1. 90% of ectopic pregnancies are tubal (in Fallopian tube, often the right one)
        2. 3/4 are identified in the first trimester
        3. Structures other than uterus not adapted to support growth of fetus, especially Fallopian tubes
        4. High risk of rupture of tube, leading to hemorrhage and death
        5. Termination of tubal pregnancy essential to preserve mother's life
      3. Placental problems
        1. Placenta previa
          1. Occurs in 1/200 deliveries
          2. Implantation near cervix causes placenta to develop across or adjacent to cervix
          3. May require bed rest during part or all of pregnancy and a Caesarian delivery
        2. Premature separation of placenta
          1. Occurs in approx. 1/150 deliveries (fetus dies in 1/500 to 1/750 deliveries)
          2. Placenta separates from uterine wall before 3rd stage of labor
          3. Causes fetal distress and damage due to oxygen deprivation
          4. May cause maternal hemorrhaging and fetal oxygen deprivation, resulting in 0.5-5% chance of maternal death and 20-35% chance of fetal death
    2. Hypertensive disorders (high blood pressure)
      1. Preeclampsia (milder) to eclampsia (severe)
      2. Also called toxemia of pregnancy
      3. More common in 1st pregnancies, and in the last half of pregnancy (after 20 weeks)
      4. Mild preeclampsia
        1. Increase in blood pressure
        2. Sudden weight gain, possibly due to fluid retention
        3. Edema (swelling)
        4. Protein in urine
      5. Severe preeclampsia
        1. Greater increase in blood pressure
        2. Headaches
        3. Vision problems
        4. More protein in urine
      6. Eclampsia (only 5% of preeclamptics progress to this point)
        1. Convulsions, shock, death
        2. 15% maternal deaths, 20% fetal deaths
    3. Infectious disease
      1. Bacterial
        1. Gonorrhea (if infected during vaginal delivery and not treated, baby may have gonococcal ophthalmia--blindness)
        2. Syphilis (crosses placenta to infect fetus--if mother has untreated secondary syphilis, baby is born with congenital syphilis)
      2. Rubella virus (many other viruses can also cause problems)
        1. Mild infection for mother
        2. If mother has infection in 5th - 10th week, severe damage to fetus
        3. Blindness, deafness, heart defects (congenital rubella syndrome)
        4. If infant is born with active infection, can spread to other infants in nursery
        5. Vaccine for rubella not usually given to pregnant women--live virus vaccine may be slightly risky to fetus
        6. Blood test can establish state of immunity of mother
      3. Toxoplasmosis (protozoan)
        1. Cysts of protozoan inhaled from dust from cat litter boxes, or ingested in poorly cooked meat
        2. Protozoan crosses placenta, causing death, CNS damage, eye problems
        3. Uncommon, since most people in this area have protective immunity, but people who move into an area where toxoplasmosis is endemic may not be immune
    4. Other medical disorders
      1. Diabetes
        1. Insulin deficiency or resistance causes poor utilization of glucose by cells, leading to high blood glucose levels with many toxic effects
        2. Pregnant diabetic should carefully control blood glucose levels, with diet, drugs, or insulin
        3. Insulin requirement varies during pregnancy--dose may need to be adjusted frequently
        4. Often have large fetus that may require Caesearian delivery
        5. Other fetal problems due to fetal exposure to high glucose levels
      2. Gestational diabetes
        1. Temporary diabetes during pregnancy--goes away after delivery
        2. 80% of women who have gestational diabetes develop type 2 diabetes within 5 years
      3. Rh disease
        1. Rh+ women have Rh molecules on surface of red blood cells; Rh- women do not
        2. If an Rh- woman is pregnant with an Rh+ fetus for the first time, there are no problems for that fetus, but at delivery, some fetal blood may mix with maternal blood, exposing her to Rh molecules for the first time
        3. Her immune system recognizes Rh molecules as foreign and reacts by making anti-Rh antibodies which circulate in her blood
        4. If she again becomes pregnant with an Rh+ fetus, the anti-Rh antibodies may cross the placenta and destroy fetal Rh+ red blood cells
        5. The destruction of fetal red blood cells makes the fetus anemic--too few red blood cells to carry oxygen
        6. Can be treated by fetal (intrauterine) or newborn transfusion with Rh- blood
        7. Can be prevented by giving Rh- woman (pregnant with Rh+ fetus or fetus of unknown Rh type) Rhogam shots during pregnancy to prevent development of anti-Rh antibodies
        8. Rhogam must be given in every pregnancy, miscarriage, or induced abortion to protect fetus in subsequent pregnancies
  • Childbirth
    1. Stage 1 of labor
      1. Uterine contractions dilate and efface cervix (widen opening and flatten walls)
      2. Contractions regular, fairly predicable
      3. Pain manageable, continued breathing helps
      4. May last 9 to 36 hours, depending on many factors
      5. Shorter if labor induced with pitocin (oxytocin)
      6. Longer labor is gentler for fetus unless it becomes too prolonged, exhausting the mother and putting the fetus at risk
      7. Near end of stage 1, reach short (45 min. - 1 hr.) phase called transition--shorter harder contractions, less predictable, less manageable, mood changes, irritability
      8. By end of stage 1, cervix is dilated to 8 to 10 cm
    2. Stage 2 of labor
      1. Signalled by urgent need to push fetus out
      2. Contractions of uterus more vertical, more powerful--tend to push down on fetus at the same time as uterine wall pull up
      3. Shorter stage than stage 1
      4. Ends with delivery of baby
    3. Stage 3 of labor
      1. Separation of placenta from wall of uterus
      2. More contractions to expell placenta from uterus
      3. Should be examined carefully to make sure all placental tissue has been removed from uterus