Endocrinology of Pregnancy, Normal Pregnancy, Puerperium, and Lactation

Ovulation Diagram

Have follicles → start to mature but one becomes primary/mature follicle → where egg will be released

Egg meets sperm and embeds in uterine lining

• Corpus luteum continues and feeds the pregnancy

No pregnancy → corpus luteum becomes corpus albicans and dies off

Fertilization and Implantation Diagram

Implantation Diagram

• Embryo enters uterine lining: starts to embed

• As it embeds there is disruption that can cause implantation spotting

What is the first sign of pregnancy (urine or blood)?

hCG hormone

What is hCG produced by?

The placenta

When does hCG rise during a normal pregnancy?

1st trimester

• 10-11 days after conception

• Doubles every 48-72 hours

Blood hCG test will not be (+) after a certain amount of time (8-11 weeks), but urine hCG will remain (+) throughout the pregnancy and for a little time after

When is hCG elevated with (5) and what is it a marker of (3)?

Elevation of hCG with:

• Normal placental tissue

• Multiple gestation

• Hydatidiform moles

• Choriocarcinoma

• Ectopic pregnancy

Marker of:

• Pregnancy (+ test)

• High values: trophoblastic disease, multiple gestation, molar pregnancy

• Low values: threatened miscarriage, ectopic pregnancy, incomplete miscarriage

What is important to note about hCG?

• Number doesn’t matter as much as the change in the number

What is the role of hCG? (1)

• Stimulates the corpus luteum to produce progesterone and estrogen to maintain the pregnancy

What is hPL produced by?

• The placenta

What are the roles of hPL? (2)

• Regulates maternal glucose, fat, and protein metabolism for fetal nutrition

  • Increases maternal insulin resistance to raise blood glucose levels for the fetus (why we do 1 hour glucose test)

• Prepares the breasts for lactation

What is prolactin produced by?

• Anterior lobe of the pituitary gland

What is the role of prolactin? (1)

• Prepares the mammary glands for lactation: increases as pregnancy progresses and peaks near delivery

What is relaxin produced by?

• Corpus luteum

• Placenta

• Decidua (uterine lining during pregnancy)

What are the roles of relaxin? (3)

• It relaxes the ligaments in the pelvis and softens the cervix in preparation for labor (may cause back pain)

• It may help prevent uterine contractions in early pregnancy

• It contributes to increased flexibility of the pelvis during delivery

What is oxytocin produced by?

• Hypothalamus → released from PPG

What are the roles of oxytocin? (3)

• Simulates uterine contractions during labor: levels rise significantly during labor

• Facilitates bonding between mother and baby

• Plays role in milk ejection during breastfeeding

What is progesterone produced by?

• Initially produced by corpus luteum

• After 10 weeks: placenta

What are the roles of progesterone? (4)

• Pregnancy hormone: crucial for maintaining pregnancy

• Maintains endometrium for implantation

• Inhibits uterine contractions to prevent preterm labor

• Prepares breasts for lactation by promoting gland development

• Progesterone both inhibits and is needed for pregnancy: depends on the time of the cycle

  • Second half of cycle: will help with pregnancy

  • After period: d/c

What are the roles of estrogen (primarily estriol but also some estrone and estradiol)? (5)

• Promotes uterine growth to accomodate the fetus

• Increases blood flow to the uterus and placenta

• Helps develop the placenta

• Triggers development of fetal organs

• Stimulates development of mammary glands for lactation (alveoli)

hCG, estrogen, and progesterone

• The correct balance of these sustains and supports pregnancy

• Together, these hormones thicken the uterine lining and tell the body to stop menstruating

Placenta and Uterus

• Placenta and uterus should be separate structures but have many blood vessels that temporarily attach them

What are the presumptive symptoms to make a diagnosis of pregnancy? (6)

• Amenorrhea

• Breast changes/tenderness

• Frequent urination (from hCG)

• Fatigue

• Mood changes due to hormones

• N/V

Enlargement of the Abdomen

• Week 12: symphysis pubis

• Week 20: umbilicus (20 weeks = 20 cm)

• Weeks 36-38: right under sternum

• Week 40: fundus drops below 38 week level as presenting part drops down into the pelvis

• After 20 weeks, the height of the fundus should equal the number of weeks

Uterine and Cervical Changes Associated with Pregnancy

Hegar sign

• Softening of the uterus/cervix (relaxin hormone)

• Seen around 4th-12th week

Chadwick sign

• Blue discoloration of the cervix

• 30% of CO is going to the pelvis

• Seen around 6th-8th week

Leukorrhea

• Excess discharge: need to make sure there is no odor/color (need to rule out vaginitis) and if the person is known to be pregnant that they have not broken their water

• From hormone stimulation

Braxton-Hicks Contractions

• Painless pressure caused by tightening of the uterine muscles

• Begins around 28 weeks and varied: resolves with exercise and hydration

  • Want to make sure that they are resolving

Endocrine Pregnancy Tests

• Urine pregnancy test

• Quantitative serum hCG: more accurate

Prostaglandins

• Not true hormones

• PGE2, PGF2, prostacyclin, thromboxane A2: made in endometrium, myometrium, fetal membranes, decidua, and placenta

  • Concentration of PGE2 and PGF2 in the amniotic fluid rises in pregnancy and in labor

• Roles of PGE2 and PGF2

  • Contraction of uterus: play major role in initiation and control of labor

  • Prevent significant blood loss in labor

  • Provokes myometrial ischemia to accelerate labor

• Various synthetic prostaglandins are used to terminate pregnancy or to induce labor at term

  • Misoprostol used for pregnancy termination and labor induction

Identification of Fetal Heart Beat

• 8-9 weeks by U/S (can be earlier but sometimes early U/S can be frustrating as not everything is seen on U/S)

• Should be around 120-160 bpm

U/S Findings

Week 5

• Diamond ring sign: embryo and yolk sac (yolk sac feeds the embryo until the placenta takes over in week 12)

Week 6-8

• Fetal heart

Pregnancy Structures Timeline

Do not need to memorize

Pregnancy Dating

• EDD/EDC: estimated date of delivery

• Nagele’s rule: method to estimate due date

  • Identify last known menstrual period (start of it) and add one year (unless the date is January to March because the due date falls within the same year), subtract 3 months, and add 7 days

  • Based on the assumption of normal 28 day menstrual cycle and ovulation on day 14

  • Abnormal cycles: add number of days beyond 28 day cycle

  • Not expected to be able to calculate it

  • Can also use the last ultrasound date as the starting date

First Trimester

• Last menstrual period through weeks 12.6

• S/S

  • Nausea

  • Fatigue

  • Breast tenderness

  • Urination

• If there is bleeding:

  • Spontaneous abortion is most common

  • From implantation

  • Sub-chorionic hemorrhage/hematoma

    • Can get cluster of blood from ruptured blood vessel and can sometimes work its way out

    • Very common

  • Intercourse/increased activity

Second Trimester

• 13-27.6 weeks of gestation

• S/S

  • Generally feeling well

  • Pain/pulling (round ligament pain)

  • Braxton-Hicks

  • Bleeding

    • Most commonly caused by placenta previa (placenta covering the cervix): concerning because patient cannot labor and will need a C-section (may not stick with them the whole pregnancy but need to monitor)

• Complications

  • Incompetent cervix

  • PPROM

  • Pre-term labor

Third Trimester

• 28-40 weeks of gestation

• S/S

  • Braxton-Hicks

  • Low back/leg pain

  • Lightening: baby drops lower in the pelvis

  • Fetus with movements rather then kicks due to increasing size and less room to move

  • Bleeding: bloody show, placenta previa, abruption (uterus separates from placenta)

  • Rupture of membranes

• Labor contractions → dilation and effacement

Maternal Weight Gain

Depends on:

• Pre-pregnancy BMI

• Other factors

Benefits

• For the baby

  • Supports proper growth and development

  • Reduces the risk of low birth weight or pre-term delivery

• For the mom

  • Reduces the risk of complications such as gestational DM, HTN, or C-section

  • Helps with postpartum recovery and returning to pre-pregnancy weight

Normal BMI and singleton

• 25-35lbs weight gain recommended

• ½ lb/week for 28 weeks

• 1 lb/week after 28 weeks

• Calories: 300-500 extra per day

Underweight

• BMI < 18.5

• 28-40 lbs weight gain recommended

Obese

• BMI > 30

• 11-20 lbs weight gain recommended

Do not need to memorize

Fetal Growth and Development

Fetal weight

• 8 weeks: 1 gram

• 28 weeks: 1,000 grams (> 2 lbs)

• 36 weeks: 2,500 grams (5.5 lbs)

• 40 weeks (term): 3,400 grams (7.5 lbs)

Surfactant

• Critical substance produced in the lungs that enables proper lung function and breathing: plays a key role in fetal lung maturity

• Lipid-protein compound produced by type II alveolar cells

• Function: lowers surface tension in the alveoli, preventing collapse during exhalation

• Babies born < 34 weeks are at higher risk of RDS due to insufficient surfactant production

Do not typically test for fetal lung maturity anymore

• Does not reliably predict neonatal outcomes and should not guide delivery timing

• Used to be performed when pre-term delivery was anticipated

• Usually give them betamethasone to mature lungs and then deliver: do not delay delivering

Fetal Status: Lie

• Relation of long axis of fetus to long axis of mother

  • 90%: longitudinal

Fetal Status: Presentation

• The part of the fetus that first enters the maternal pelvis

  • Cephalic: vertex, face, brow

  • Breech: frank, complete, footling

Fetal Status: Attitude/Habits

• Positioning of the fetal body parts relative to one another (posture)

  • Vertex:

    • Complete flexion

    • Optimal for labor and delivery

    • Allows the smallest head diameter to pass through the birth canal

  • Military

    • Moderate flexion

    • May result in longer or more difficult labor as the larger head diameter must pass through the pelvis

  • Extension:

    • Increases the likelihood for brow or face (hyper-extended) presentation

    • Can lead to complications: prolonged labor, assisted delivery, C-section

Fetal Status: Position

• Relationship of a designated fetal reference point (usually occiput) to the maternal pelvis

  • Usually want to see LOA

Fetal Status: Station

• The level of descent of the presenting part of the fetus above or below the plane of the ischial spines

• Ranges from -3 to +3

Puerperium

Period 6 weeks after delivery

• See involution of 5-6 weeks

• Lochia (vaginal discharge) lasting 3-4 weeks

  • Rubra: first stage

    • Dark red in color and around 4 days long

  • Serosa: second stage

    • Pinkish in color and lasts for 10 days

  • Alba: third stage

    • Whitish yellow and lasts for 10-14 days

• Diuresis days 2-5

  • Do have risk of UTI

• Blood: leukocytosis at labor

• Menstruation: lactating vs non-lactating

• Complications

  • Hemorrhage

  • Infections

What is a lack of breast feeding associated with in the child?

Obesity

• Breast feeding provided protective benefits against obesity later on in life

• Longer duration of breastfeeding associated with greater reduction in obesity risk

• Reasons

  • Better appetite regulation: formula fed infants may be encouraged to finish bottles, overriding satiety clues

  • Hormonal composition: breast milk contains hormones that regulate energy balance and fat storage

  • Microbiome development: fosters growth of healthy gut microbiome

Breastfeeding and Maternal HTN

• Longer durations of breastfeeding associated with greater benefit in blood pressure

• Women who breastfed are less likely to develop HTN during menopause

• Mom’s with pre-existing HTN may not experience the benefit

• Reasons

  • Hormonal effects: breastfeeding promotes the release of oxytocin, which lowers BP by relaxing blood vessels and reducing stress levels

  • Cardiovascular: lowers cholesterol and triglyceride levels and enhances glucose regulation

  • Weight regulation: faster postpartum weight loss

Hormones Involved in Lactation

• Prolactin: milk production

• Oxytocin: milk let-down

Milk Components

• Carbs and fat: energy

  • The mom makes milk that has exactly what the baby needs (stimulated from latching)

• Immunity/antibodies

• Colostrum

  • Started food: babies stomach is so small that they have this in smaller doses and more frequently for 2-3 days postpartum

  • Yellow

  • High protein, Vitamin A, sodium, chloride, immunoglobulin

  • Low carbs and low fat

Breastfeeding Recommendations

• Exclusive breastfeeding for first 6 months of life

• Continued breastfeeding for at least 12 months while gradually introducing complementary foods beginning around 6 months

• By 12 months: breastfeeding can continue for as long as mutually desired by mom and baby for 2 years or beyond

Breastfeeding Benefits for Baby (8)

• Provides nutrition

• Digestible

• Available at right temperature

• Free from bacterial contamination

• Reduces risk of infections

• Lowers risk of chronic conditions

• Promotes cognitive development

• Proper development of jaw/teeth/brain

Breastfeeding Benefits for Mom (5)

• Reduces risk for postpartum hemorrhage (contracts the uterus)

• Lowers risk of breast and ovarian cancer

• Reduced risk of hypotension and DMI II

• Promotes bonding

• Economical

Challenges to breastfeeding (7)

• Separation of newborn and mom in hospital

• Not enough uninterrupted time in hospital

• Breastfeeding is not easy: both need to learn

• Moms need support: babies can be fussy

• Pumping milk takes time

• Need space and support at work

• U.S. culture not fully supportive

Absolute Contraindications to breastfeeding

Maternal

• HIV infection

• Human T-cell lymphotrophic virus infection

• Untreated brucellosis

• Suspected or confirmed Ebola

• Active chemotherapy: may resume after 3 week safety window following last dose

Infant

• Classic galactosemia

Temporary Contraindications to breastfeeding

• Active TB

• Varicella disease

• Active herpetic breast lesions

• Illicit substance use

  • Moms on stable methadone or buprenorphine maintenance therapy are encouraged to breastfeed

Pasteurized Donor Human Milk (PDHM)

• PDHM specifically recommended while baby is in NICU for low birth weight (< 1500 grams)

• Recommends this from established milk banks when mother’s own milk is unavailable, insufficient, or contraindicated

• Discouraged informal milk sharing and purchasing milk from internet based sources

  • Informal milk sharing may be associated with infectious risks and contaminants

Techniques of breastfeeding

• Rooting

• Detaching infant

• Avoid bottle (until breastfeeding is well established → 4-6 weeks)

• Feed on demand

• Newborns can take 20-45 minutes per feeding every 2-3 hours

Signs of adequate milk production

• Baby gaining weight appropriately

• Appears satisfied after feedings

• Breasts soft after feeding

• Wet diapers produced

Suppression of Lactation

• Gradually wean off nursing

• Cold compresses

• Supportive and well-fitting bra

• Avoid breast stimulation

• Hydrate (not too much)

• Avoid lactogenic foods

• Pain relief: ibuprofen/Tylenol

• Herbal remedies: sage or peppermint

• Medications: reserved for medical reasons

  • Dopamine agonists (cabergoline or bromocriptine): inhibit prolactin