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pregnancy (gestation)

Childbirth generally occurs ~ 38 weeks after conception or ~ 40 weeks from the last normal menstrual period. Contraindications: - hypertrophic cardiomyopathy - ventricular outflow tract obstruction - LV systolic dysfunction with LV ejection fraction < 40% & class 3 or 4 heart failure [2] - severe pulmonary hypertension Physiology: === Cardiology === 1) hemodynamic changes: a) increased plasma volume (1100-1500 mL) b) increased red cell mass (300 mL) c) increased cardiac output d) heart rate increase 20-30% (< 100/min) e) blood pressure 1] decreases soon after conception 2] reaches a nadir in 20 weeks f) hypertension affects 10% of pregnant women 1] blood pressure (BP) > 140/90 2] increase of systolic BP of > 30 mm Hg 3] increase of diastolic BP of > 15 mm Hg 2) auscultation a) systolic ejection murmur in pulmonic area, not more than III/VI is a normal finding during pregnancy b) 3rd heart sound (S3) is common in pregnancy; S4 heart sound is pathologic c) grade 1-2/6 systolic murmur normal d) grade 3/6 systolic murmur or any diastolic murmur is pathologic e) diastolic rumble should raise suspicion of mitral stenosis 3) absolute contraindications to pregnancy a) Marfan syndrome with dilated aortic root 1] increased risk of dissection & rupture due to hormonal- induced softening of connective tissue 2] unpredictable risk of dissection & rupture, regardless of aortic size b) Eisenmenger's syndrome (50% maternal mortality) c) primary pulmonary hypertension d) symptomatic aortic stenosis e) symptomatic mitral stenosis f) symptomatic dilated cardiomyopathy 4) heart failure a) mild dyspnea on exertion is normal b) orthopnea, paroxysmal nocturnal dyspnea pathologic c) minimize activity to decrease cardiac output d) reduce sodium in diet e) minimize anemia: vitamin & iron supplements f) avoid ACE inhibitors, ARBs, aldosterone antagonists 5) arrhythmias a) atrial premature contractions normal b) ventricular premature contractions normal c) atrial fibrillation, atrial flutter, ventricular tachycardia are pathologic d) cardioversion may be performed if necessary - simultaneous monitoring of fetal heart 6) surgery a) during 1st trimester associated with increased fetal loss b) percutaneous balloon valvuloplasty well tolerated 1] aortic, mitral & pulmonary valvuloplasty 2] lead shielding of fetus 7) pharmaceutical agents a) contraindicated - captopril, phenytoin, warfarin, tetracycline b) drugs which cross placenta, but may be used safely 1] digoxin, quinidine, procainamide, verapamil 2] beta blockers a] monitor fetal growth b] may be associated with fetal growth retardation, neonatal bradycardia & hypoglycemia 8) delivery a) average blood loss 1] 500-800 mL with vaginal delivery 2] 800 mL with cesarean section b) with each uterine contraction, 500 mL of blood is released into the circulation c) no need for antibiotic prophylaxis for uncomplicated vaginal delivery 9) prosthetic valves a) most women of child-bearing age who need valve replacement receive bioprosthetic valves b) generally, they do not receive anticoagulation c) in pregnant women with mechanical valves, switch from warfarin to subcutaneous heparin d) heparin is associated with increased fetal loss * pulmonary edema is pathologic === Nephrology: (Renal) === 1) renal enlargement (1 cm) [30] 2) dilatation of the renal calyces, pelvis & ureters - features can resemble obstructive uropathy [2] - increases risk for ascending pyelonephritis [2] 3) 30-50% increase in glomerular filtration rate (GFR) & renal blood flow 4) decrease in serum creatinine [2] - mean serum creatinine of 0.5 mg/dL, 0.8 mg/dL (max) 5) mean urea nitrogen of 18 mg/dL, 26 mg/dL (max) 6) intermittent glycosuria (< 1 g/day) independent of plasma glucose 7) proteinuria a) normal < 300 mg/day, may be postural b) women with underlying renal insufficiency may have a significant increase in proteinuria during pregnancy associated with poorer fetal prognosis, not associated with any worsening of their renal disease [2] c) women with diabetes mellitus type-1 with microalbuminuria but normal renal function & blood pressure have pregnancy outcomes similar to the general population [2] 8) increased uric acid secretion 9) increased ureteral peristalsis 10) 50% increase in plasma volume 11) increased total body water (6-8 L) with osmostat resetting - mildly diminished plasma osmolality [2] 12) changes in sodium metabolism (not uncommon) a) mild hyponatremia due to changes in ADH response to osmolality b) renal sodium retention 13) decrease in blood pressure [2] 14) hypertension, proteinuria, or elevated serum creatinine during the first antepartum visit suggests chronic glomerulonephritis === Endocrine === 1) increased plasma levels of a) renin b) angiotensin II c) aldosterone d) cortisol e) estrogens f) prostaglandins E2 & I2 g) progesterone 2) insensitivity to pressor effects of: a) angiotensin II b) norepinephrine 3) progesterone counteracts K+ excreting effects of aldosterone 4) 30-50% increase in requirement for thyroxine a) similar increase in requirement for iodine [2] b) subclinical hypothyroidism may adversely affect outcome [6] === Immunology === 1) 3rd trimester is associated with immunosuppression 2) defects in neutrophil chemotaxis 3) defect in T-cell mediated cellular immunity 4) risk of disseminated Herpes zoster 4) risk of disseminated coccidioidomycosis === Hematology === 1) anemia a) decrease in hemoglobin as low at 10 mg/dL b) increase in plasma volume (1100-1500 mL) c) lesser increase red cell mass (300 mL) d) reduced viscosity of blood e) iron deficiency generally involved 1] iron preferentially routed to fetus 2] 1000 mg of iron generally required per pregnancy a] blood loss b] fetal requirements 2) aplastic anemia may be associated with pregnancy a) resolves with termination of pregnancy b) may recur with subsequent pregnancy 3) sickle cell disease a) increased maternal mortality b) increased fetal morbidity c) prophylactic transfusion is NOT of benefit 4) thrombocytopenia a) mild gestational thrombocytopenia (> 75,000/uL) in 8.3% 1] generally develops in 3rd trimester 2] no specific treatment needed b) chronic immune thrombocytopenic purpura (ITP) 1] may be worsened by pregnancy 2] IgG of ITP crosses placenta 3] prednisone is 1st line 4] IV immune globulin if refractory to prednisone c) HELLP syndrome 5) hemorrhagic disorders a) factor VIII autoantibodies b) factor VIII-vWF complex increases in 2nd trimester with a rapid decrease post-partum 6) thrombotic disorders a) pregnancy should be considered a hypercoagulable state 1] concentration of procoagulant factors increase progressively during pregnancy 2] protein S & fibrinolytic activity decrease - C4b binding protein increases during pregnancy decreasing the amount of free (& functional) protein S 3] coagulation cascade may be activated in the placenta 4] increased venous stasis in lower extremities 5] labor & delivery, especially C-section increase risk of thrombosis b) normal levels of plasma fibrinogen in the 3rd trimester of pregnancy is about twice the non-pregnant state c) disseminated intravascular coagulation (DIC) 1] most common thrombotic disorder in pregnancy 2] abruptio placenta is the most common cause of DIC 3] amniotic fluid embolism 4] intrauterine fetal death 5] saline-induced abortion 6] septic abortion 7] frequent association with fatty liver of pregnancy d) placental tissue factor or activated clotting factors entering the mother's circulation may trigger DIC === Dermatology === 1) hyperpigmentation [2] 2) striae gravidarum 3) hair & nails - hair may thicken during pregnancy with telogen effluvium occurring 3 months post partum - nails may grow faster during pregnancy 4) vascular changes [2] - spider angiomas - hemorrhoids & varicose veins - palmar erythema - peripheral edema in 35-85%* - vaginal erythema (Chadwick sign) - blue discoloration of the cervix (Goodell sign) - gingival hyperemia & edema === General === 1) higher risk for stillbirth > 40 years of age 2) risk of genetic abnormalities accelerates after 35 years of age 3) nausea/vomiting of pregnancy reduces risk of spontaneous abortion [13] Laboratory: - urinalysis for asymptomatic bacteriuria (all women) - increased risk for pyelonephritis [2]; treatment indicated [2] - complete blood count for iron deficiency anemia - workup anemia - hepatitis B serology - syphilis serology [2] - blood type & screen - serum TSH - serum progesterone predicts viability in early pregnancy [10] - serum 25-OH vitamin D in women with immediated family member with multiple sclerosis [35] - urine drug screen on 1st visit (all pregnant women) [39] - serum sodium: mild hyponatremia from a reset in ADH response to low osmolality is normal & does not require treatment [2] Complications: - see pregnancy disorder - short interpregnancy interval is not associated with adverse outcomes [17] - weight gain between pregnancies increases risk for adverse birth outcomes (stillbirth, neonatal mortality) [27] - increased risk for pyelonephritis [2] - loss of husband (father of child) during pregnancy associated with shortened adult life span in offspring [37] - women > 40 years of age at higher risk than women 20-34 years for adverse events (chromosomal aberrations, miscarriage, & preterm birth) 11% vs 5% [42] - women with chronic renal failure at increased risk for pre-eclampsia, progression of chronic renal failure, ESRD, preterm delivery, gestational hypertension, intrauterine growth retardation & spontaneous abortion [2] - thrombosis & thromboembolism are the leading cause of death [43] Management: - preconception risk assessment (see conception) - folic acid 0.4-0.8 mg QD* [36] - begin at least 1 month prior to conception & continue for 2-3 months after delivery - calcium supplementation for prevention of pre-eclampsia in populations where calcium intake is low [NGC, WHO] - increase levothyroxine dose in women with hypothyroidism 30-50% prior to conception or when pregnancy discovered if unplanned [2] - vitamin D supplementation - little effect on maternal or neonatal outcomes [41] - vitamin D (1000 IU QD) beginning at 14-17 weeks gestation may increase bone mineral content among infants born in winter months [28] - maternal serum 25-hydroxy vitamin D declines from 14-34 weeks gestation in women who deliver in winter & spring unless supplemented with vitamin D [28] - maternal vitamin D deficiency duing pregnancy associated with increased risk of multiple sclerosis in offspring [29,35] - 1000-2000 IU vitamin D daily for women with immediate family member with multiple sclerosis & serum 25-OH vitamin D < 20 ng/mL [35] - vaccinations - Tdap after 20 weeks gestation (all pregnancies) [12,25]; 27-36 weeks of gestation [33] - dT q 4 weeks x 2 after Tdap if not previously vaccinated for tetanus [8] - influenza vaccine can be given any trimester [8] - influenza vaccination between 20 & 36 weeks' gestation reduces influenza in mothers & their infants (2-4% both) [18] - does not reduce influenza in infants of HIV+ mothers [18] - measles/mumps/rubella vaccine (MMR) & varicella vaccine - immediately postpartum in nonimmune women [21] or - >= 4 weeks prior to conception (live virus vaccine) [2] - dietary interventions during pregnancy limit maternal weight gain & reduce risk for some maternal complications [9] - a healthy diet may reduce risk of pre-term delivery [14] - weight gain targets: [11,38] - pre-pregnancy BMI < 18.5 (underweight): 28-40 pounds - pre-pregnancy BMI 18.4-24.9 (normal): 25-35 pounds - pre-pregnancy BMI 25.0-29.9 (overweight): 15-25 pounds - pre-pregnancy BMI > 30 (obese): 11-20 pounds [11,38] - ACOG recommends daily physical activity/exercise during pregnancy & the postpartum period [26] - diet & exercise during pregnancy may affect incidence of macrosomia (> 4000 g) [14] - exercise during pregnancy reduces risk of macrosomia & does not increase risk for small babies (<2500 g) [34] - physical activity during pregnancy either decreases duration of labor or has no effect on it [34] - pregnant & breast-feeding women should eat of a variety of fish two to three times a week (8-12 oz weekly) to support growth & development [15] - the fish should be low in methylmercury - prenatal & postpartum home care may reduce maternal & child mortality [16] - topical agents are often preferred during pregnancy because of lower risks for systemic effects [2] - exception is topical tazarotene pregnancy category X - antipsychotic use during pregnancy - risk of extrapyramidal signs in infants born to mothers taking antipsychotics in the 3rd trimester of pregnancy [23] - associated with minimal risk during pregnancy [24] - general surgery as safe for pregnant women as it is for nonpregnant women [22,40] * folic acid fortification of cereal grains prevents > 1300 neural tube defects annually [19] * folic acid supplementation in high-risk pregnancy is only 37% [20] Notes: - a pregnant woman capable of decision making should be allowed to decline recommended medical or surgical interventions [32] - directed counseling is recommended, but do not try to coerce women into making a specific decision - attempt to understand context of the decision & acknowledge prognostic uncertainty - consider ethics consult experts if it may help resolve the conflict - no action should be taken against clinicians who decline to perform court-ordered interventions

Related

alcohol during pregnancy immunization during pregnancy; maternal immunization medications contraindicated during pregnancy medications during pregnancy pregnancy category pregnancy disorder; obstetric disorder; pregnancy complication pregnancy test prenatal care SARS CoV2 & pregnancy & breastfeeding

Useful

abortion conception fetus labor & delivery miscarriage

Specific

high-risk pregnancy intrauterine pregnancy multigravida multiple gestation (multiple pregnancy) post-term pregnancy; prolonged pregnancy primigravida surrogate pregnancy teen birth; teenage pregnancy term pregnancy unintended pregnancy

General

reproduction

References

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