Preconception and Antepartum Care
Naegele rule
add 7 days to the first day of the last normal menstrual flow and subtract 3 months -to establish accurate gestational age, date of onset of the last normal menses is crucial -US established dates should take preference over menstrual dates
Constipation
↑ fluid intake and increased bulk with fruits and vegetables -docusate, psyllium fiber, and lubricants
Human chorionic gonadotropin (hCG)
-produced in the syncytiotrophoblast of the growing placenta -shares an a-subunit with LH, so need to differentiate -Maintains the corpus luteum until the placenta can secrete enough progesterone -Also promotes male sexual differentiation and stimulated thyroid gland -Standard laboratory urine pregnancy tests positive 4 weeks following first day of LMP (around time of missed period) -Home urine test has high false-negative rate -All urine pregnancy tests best performed on early-morning urine specimens, which contain the highest concentration of hCG Serum test-more specific/sensitive as tests for unique B-subunit of hCG, -test positive before missed period -mean doubling time for hCG in patients with viable intrauterine pregnancy is 1.5-2 days.
Fetal activity
-time necessary to achieve certain number of movements each day, counting number of movements (kick counts) in a given hour
Normal Fetal HR
110-160, with higher rates earlier in pregnancy
trisomy 21 (Downs)
2 up, 2 down ↓ AFP, ↓ estriol, ↑ B-hCG, ↑ inhibin A
Laboratory and Screening Tests 24-40 weeks
24-28 weeks: One hour glucose challenge for gestational diabetes 28-30 weeks: RHoGAM for Rh (-) women 35-37 weeks-GBS and resistance testing if PCN allergic Cultures for group B streptococcus are not required in women who have group B streptococcal bacteriuria during the current pregnancy or who have previously given birth to a neonate with early-onset group B streptococcal disease because these women should receive intrapartum antibiotic prophylaxis. 35-40 weeks: GC/chlam, HIV, RPR in high risk
Exercise
30 minutes of moderate exercise/day accept;e -supine exercises should be discontinued after first trimester to minimize circulatory changes brought on by pressure of uterus on vena cava. -sitting in hot tub/sauna not recommended, as hyperthermia might be teratogenic
Laboratory and Screening Tests 0-20 weeks
9-14 weeks: PAPP-A, nuchal transparency, free HCG +/- CVS (aspiration placental tissue) 15-22 weeks: Offer MSAFP or quad screen (AFP, estriol, BHCG, inhibit A) +/- amniocentesis -amniocentesis indicated for >35 YO, after abnormal quad screen, Rh-sensitized pregnancy to obtain fetal blood type or hemolysis, to evaluate fetal lung maturity via L/S ratio>2.5 18-20 weeks: ultrasound for full anatomic screen
Gestational HTN
>140/90 w/o proteinuria -BP generally declines at end of first trimester and rises in 3rd trimester develops at 20 weeks GA, as many as 25% go on to develop preeclampsia
Transcranial doppler
>20 weeks -dx fetal anemia -replaced PUBS
Breastfeeding
Benefits for newborn -nutrition, immunologic protection Benefits for mother -more rapid uterine involution, economy, maternal-child bonding, natural contraception, and more rapid weight loss a/w extra caloric expenditure
Ultrasound exam
Abdominal US-detects gestational sac 5-6 weeks after beginning of last normal menstrual period (B-hCG 5000-6000) Trransvaginal US-detects pregnancy at 3-4 weeks gestation (1000-2000) -B-hCG of 1500 is cutoff beyond which an intrauterine gestational sac should be visualized when ruling out an ectopic pregnancy -If B-hCG>4000, embryo should be visualized and cardiac activity detected by US -First-trimester US done to confirm presence of intrauterine pregnancy, estimate gestational age, diagnose and evaluate multiple gestations, confirm cardiac activity -also useful for evaluating vaginal bleeding, suspected ectopic pregnancy, and pelvic pain -look for nuchal translucency to help diagnose chromosomal abnormalities like Down syndrome, trisomy 18, 13, Turner syndrome Can evaluate placental and cervical abnormalities as well like Color-flow Doppler US (placenta accrete) or TVUS for placenta previa
Hepatitis C during pregnancy
All those with HCV should be immunized against Hep A and B, as acute hepatitis can be life threatening
Biophysical profile
BPP is series of 5 assessments of fetal well being, each of which is given score of 0 or 2 -Modified BPP combines use of an NST and assessment of an amniotic fluid index -AFI is a semiquantitative, 4 quadrant assessment of amniotic fluid depth -Diminished amniotic fluid is thought to represent ↓ fetal urinary output caused by chronic stress and shunting of blood away from the kidneys - 8-10 is reassuring, 6 is equivocal, 0-4 worrisome for fetal asphyxiation (deliver immediately)
Down syndrome
Cell-free DNA screening is the most effective screening test for Down syndrome. The test may be performed as early as 9 weeks gestation and until delivery. The test detects over 99% of cases of Down syndrome. -The quadruple test (maternal serum alpha fetoprotein, unconjugated estriol, human chorionic gonadotropin, and inhibin A) may be used to screen for Down syndrome in the second trimester. Down syndrome occurs in about 1 in 800 births in the absence of prenatal intervention. The efficacy of screening for Down syndrome is improved when additional components are added to the maternal serum alpha fetoprotein screening. The addition of unconjugated estriol and human chronic gonadotropin (the Triple Screen) results in a 69% detection rate for Down syndrome. Adding inhibin A to produce a quadruple screen achieves a detection rate of 80-85%. Nuchal translucency measurement with maternal serum PAPP-A and free Beta-hCG (known as the combined test) is a first trimester screen for Down syndrome. It detects approximately 85% of cases of Down syndrome at a 5% false positive rate.
Nutrition and weight gain
Except for iron, mineral supplementation is likewise not required in otherwise healthy women -National Academy of Science recommends 27 mg of iron supplementation (or 150 iron sulfate) -Calcium 1300 for women<19, 1000 for those>19 -For vegetarians: Vitamin D 10 ug or 400 IU/day and Vitamin B12 2 ug/day
Screening tests
First-trimester screening (10-13 weeks)-pregnancy associated plasma protein A (PAPP-A), B-hCG, and NT Second trimester screening (15-20)-quadruple screen (mater serum a-fetal protein, hCG, estriol, and inhibit) Third-trimester screening-glucose challenge test, glucose tolerance test if abnormal, Hb, Hct Repeat screening for HIV and antibodies in Rh-negative GBS screen at 35-37 weeks,
Fundal Height
From level of symphysis pubis to uppermost part of uterus -until 36 weeks in normal pregnancy, the number of weeks gestation approximates fundal height in cm. -After 36 weeks, fetus moves downward into pelvis beneath symphysis pubis (lightening), so unreliable after 36 weeks
Large for gestational age
Fundal height greater than anticipated -due to wrong gestational age, multiple pregnancy, macrosomia, hydatidiform mole, polyhydramnios
Fetal alcohol syndrome
Growth restriction, facial abnormalities like shortened palpebral fissure, low set ears, mid facial hypoplasia, smooth philtrum, and thin upper lip, microcephaly, mental retardation, and behavioral disorders like ADD
Weight Gain for Pregnancy
Historical data show that women who gained within the IOM guidelines experienced better outcomes of pregnancy than those who did not. - The recommendations are: underweight (BMI < 18.5 kg/m2) total weight gain 28 - 40 pounds; normal weight (BMI 18.5 - 24.9 kg/m2) total weight gain 25 - 35 pounds; overweight (BMI 25 - 29.9 kg/m2) total weight gain 15 - 25 pounds; and obese (BMI > 30 kg/m2) total weight gain 11 - 20 pounds.
Tobacco Use
IGR, low birth weight, and fetal mortality -nicotine replacement has not been studied
Late term complications
Induction of labor recommended to prevent complications -oligohydramnios-aging placenta may have decreased fetal perfusion, resulting in ↓ renal perfusion and ↓ urinary output
Hyperandrogenism during pregnancy
Luteoma-treat with expectant management, only surgery indicated if torsion or mass effect -high chance of virilization Theca lutein cyst-multiseptated, arise from high B-hCG levels from gestational disease or molar pregnancy -Suction curretage indicated if complete mole seen on US, otherwise regress
Contraction stress test
Measures the response of the fetal HR to the stress of a uterine contraction (via nipple stimulation or oxytocin) -performed in lateral recumbent position -result is negative if there are no change from baseline fetal heart rate and no fetal heart rate decelerations (GOOD, predictive of fetal well being) -if decelerations occur, the results can be considered positive, equivocal, or unsatisfactory -Positive: defined by late decelerations following 50% or more of contractions in 10 minute window -CI in in those with PROM, placenta prevue, uterine surgery hx, high risk preterm labor, risk to pregnancy
MSAFP
Ninety to ninety-five percent of cases of elevated MSAFP are caused by conditions other than neural tube defects including under-estimation of gestational age, fetal demise, multiple gestation, ventral wall defects and a tumor or liver disease in the patient. Incorrect dating, specifically under-estimation of gestational age, is the most common explanation for an elevated MSAFP.
Nausea and Vomiting
Most mild cases can be resolved with lifestyle and dietary changes, including consuming more protein, ginger, Vitamin B6, or B6 + doxylamine -antihistamine H1 blockers and phenothiazines for more severe cases
Modified BPP
NST + AFI -Normal test consists of reactive NST and AFI> 5 cm -Oligohydramnios (AFI <5 cm( always warrants further workup)
Carpal Tunnel Syndrome
Paresthesias/pain in the distribution of the median nerve Incidence in pregnancy is increased secondary to estrogen mediated depolymerization of ground substance, which causes interstitial edema of the hands and face -prolonged wrist flexion and extension also ↑ pressure -Rx is neutral position wrist splint, local corticosteroid injection if doesn't work -NSAIDs may lead to premature closing DA and ↑ rate miscarriage
Antenatal visits
Patients with normal pregnancy, periodic antepartum visits at 4 week intervals scheduled until 28 weeks, then every 2 weeks till 36 weeks, and weekly thereafter ask about any problems like vaginal bleeding, nausea, vomiting, dysuria, and vaginal discharge ↓ fetal movement after time of fetal viability is warning sign requiring further evaluation of fetal well-being
Fetal Maturity Assessment
Should be taken into consideration when delivering a fetus preterm or electively in high-risk pregnancies -because the respiratory system is the last fetal system to mature functionally, many tests target that -Several phospholipids, surfactant, enter the amniotic fluid where they can be obtained by amniocentesis and measured -surfactant necessary for potency of alveolar sacs -L/S ratio used to determine fetal lung maturity, as well as phosphatidylglycerol
Diagnosis of Pregnancy
Softening and enlargement of the uterus apparent at 6 weeks, palpable at 12 weeks from onset LMP -Chadwick sign-congestion and bluish discoloration of the vagina -Hegar sign-softening of the cervix ↑ pigmentation of skin and abdominal striae -patient's initial perception of fetal movement (quickening) not reported before 16-18 weeks gestation and often as late as 20 weeks 1st time mothers -Pregnancy test needed to confirm diagnosis
Neural Tube Defect Prevention
Take 0.4 mg folic acid daily while attempting pregnancy and during first trimester -women with prior NTD pregnancy or using medications that interfere with folate metabolism should consume 4 mg folic acid/day (add separate supplement to single multivitamin)
Diabetes
Women with poorly controlled diabetes immediately prior to conception and during organogenesis have a four- to eight-fold risk of having a fetus with a structural anomaly. -The majority of lesions involve the central nervous system (neural tube defects) and the cardiovascular system. Genitourinary and limb defects have also been reported. Although caudal regression malformation occurs at an increased incidence in individuals with diabetes, this condition is very rare. -High chest to head and shoulder to head ratios, plethora, fat accumulation -C section not recommended for macrosomics Fasting<90, 2 hour post prandial <120
Detection of fetal heart activity
almost always evidence of viable IUP -auscultation possible at 18-20 weeks -Doppler at 12 weeks gestation
Fetal monitoring tests
assesses fetal well-being -non-stress test, contraction stress test, BPP, and US of umbilical artery blood flow velocity
Small for gestational age
incorrect assessment of gestational age, hydatidiform mole, fetal growth restriction, oligohydramnios, or even intrauterine fetal demise
Gestational diabetes
insulin insensitivity -preconception obesity, 1 lb/week weight gain, advanced maternal age Dx: insulin→qHs at night basal, qAc with meals
Non-stress test
measures the fetal HR, patterns, and accelerations, which are monitored with an external transducer for 20 minutes -Fetal HR acceleration in response to fetal movement -FHR is monitored along with tocodynamometer to detect uterine contractions -performed when mother resting in lateral tilt position (to prevent supine hypotension) -Reactive NST: 2 accelerations >15 BPM above baseline lasting for at least 15 seconds over 20 minute period -also have to have moderate variability Nonreactive: <2 accelerations (indication to do BPP) -lack of FHR accelerations: GA<32 weeks, fetal sleeping, fetal CNS anomalies, and maternal sedative or narcotic administration
Alcohol
most common teratogen to which fetus is exposed -leading preventable cause of mental retardation, developmental delay, and birth defects in the fetus
Respiratory distress syndrome
neonates delivered before their lungs have matured, a serious and life-threatening condition caused by lack of surfactant -signs: grunting, chest retractions, nasal flaring, and hypoxia -manage with ventilation and correction of associated metabolic disturbances until neonate can ventilate w/o assistance -administer synthetic/semisynthetic surfactant -results of fetal pulmonary tests for immaturity do not have a high predictive value for RDS
Gestational age
number of weeks that have elapsed between first day of LMP (not presumed time of conception) and date of delivery
chorionic villus sampling
performed at 10-12 weeks gestation. -The procedure involves sampling of the chorionic frondosum, which contains the most mitotically active villi in the placenta. CVS can be performed using a transabdominal or transcervical approach. -The sampled placental tissue may be analyzed for fetal chromosomal abnormalities, biochemical, or DNA-based studies including testing for the mutations associated with cystic fibrosis. -CVS cannot be used to detect neural tube defects. -Omphaloceles and neural tube defects are generally diagnosed using prenatal ultrasound. Both of these conditions are associated with an increased MSAFP (maternal serum alpha-fetoprotein). -risk of fetal loss associated with CVS is approximately 1%
hyperemesis gravidarum
persistent vomiting not related to other causes, acute starvation (↑ ketonuria), and weight loss ↑ hCG and ↑ estradiol -if morning sickness persists after first trimester, consider this -Check B-hCG to rule out molar pregnancy -Evaluate for ketonemia, ketonuria, hyponatremia, and hypokalemic, hypochloremic metabolic alkalosis -Can do TVUS if suspect pathology Rx: Vitamin B6, doxylamine (antihistamine) PO, promethazine or dimenhydrinate PO/PR -if severe: metoclopramide, ondansetron, promethazine IM/PO -fluids, nutrition supplementation
HSV during pregnancy
risk for neonatal HSV infection ↑ if infant passes through vaginal canal and is exposed to active lesion -those with history of genital infection should receive prophylactic valcyclovir or acyclovir at 36 weeks -Should do Cesarean section if active lesions and risk for neonatal HSV infection
Vaccinations/Screening
should be offered to women at risk for or susceptible to rubella, varicella, pertussis, and hepatitis B -Should get influenza vaccine -all pregnant women should be tested for HIV, unless they decline the test -All for RPR as well, rubella antibody titer, GC/Chlam if <25 and ↑ risk, PPD -STDs, mantoux test for TB, sickle hemoglobinopathies, thalassemias, cystic fibrosis, Tay-sachs Avoid live vaccine within one month of pregnancy -Avoid conception after 1 month of taking live vaccination like MMR -still little risk to fetus and can resume normal routine prenatal care
External cephalic version
turn fetus from breech to vertex presentation to allow vaginal rather than cesarean delivery -done after 37 weeks if fetus still in breech position -if fails, then proceed to C section -before 37 weeks not indicated -CI in presence of multifetal gestation, fetal compromise, uterine anomalies, and problems of placentation
trisomy 18
↓ AFP, ↓ estriol, ↓B-hCG, ↓ inhibin A Still UNDERage at 18
