Fetal Demise and Fetal Malposition

Educational Objectives

The goals of this program are to improve identification of women at risk for stillbirth (SB) and improve outcomes in cases of fetal malposition. After hearing and assimilating this program, the clinician will be better able to:

1.   Recognize women at risk for SB.

2.   Discuss causes of SB.

3.   Implement a program of antenatal surveillance for women at risk for SB.

4.   Identify risk factors for and diagnose fetal malposition.

5.   Prevent and correct fetal malposition at delivery.

Faculty Disclosure

In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty and members of the planning committee to disclose relevant financial relationships within the past 12 months that might create any per­sonal conflicts of interest. Any identified conflicts were resolved to ensure that this educational activity promotes quality in health care and not a proprietary business or commercial interest. For this program, the faculty and plan­ning committee reported nothing to disclose.

Acknowledgments

Dr. Dildy was recorded at Obstetric Intensive Care: A Simplified Approach, sponsored by Scottsdale Healthcare, and held November 13-15, 2008, in Scottsdale, AZ. Dr. Shaffer was recorded at Antepartum & Intrapartum Management, sponsored by the University of California, San Francisco, School of Medicine, and held on June 11-13, 2009, in San Francisco. The Audio-Digest Foundation thanks the speakers and the sponsors for their cooperation in the production of this program.

Stillbirth: Assessment and Prevention Strategies

Gary A. Dildy III, MD, Professor, University of Utah School of Medicine, Department of Obstetrics and Gyne­cology, Salt Lake City; Director, Maternal-Fetal Medicine, MountainStar Division, Hospital Corporation of America, Salt Lake City

General considerations: »26,000 stillbirths [(SBs), »6.4 per 1000 total births)] in the United States (2002); more common than neonatal deaths; intrauterine fetal death (IUFD) 10 times more common than sudden infant death syndrome (SIDS); significant decrease in IUFD and neonatal mortality over last 50 yr; no decrease in neonatal mortality (defined by infant, neonatal and postneonatal deaths) from plateau in 1990s; no substantial change in early fetal death (20 to 27 wk gestation) over last 50 yr; steady decline in late fetal death; prenatal care credited in reducing late fetal death; data evaluating changing pattern of fetal deaths over 3 decades show significant reduction in Rh isoimmunization-related fetal deaths (due to development of intrauterine transfusion); 95% reduction in in­trapartum asphyxia-related deaths; significant reduction in intrauterine growth restriction (IUGR)-related fetal deaths; data evaluating etiology and gestational age show the earlier SB occurs, the more likely cause identifiable; identification of etiology unlikely in 50% of cases, even with comprehensive evaluation

Risk factors for unexplained SB

IUGR: low or high parity risk factor; alterations in fetal growth (either IUGR or large for gestational age); rate of SB among small for gestational age (SGA) neonates »50 per 1000 (»5%); 12-fold higher than general population or adequate for gestational age (AGA) neonates; data published from United Kingdom on etiologies of SB  —show most unexplained; malformations second leading etiology, followed by intrapartum causes (eg, uterine rup­ture, uteroplacental insufficiency, cord prolapse)

Chromosomal abnormalities (eg, Down syndrome): can be significant factor, consider with IUGR or dysmorphic features; absence of end diastolic blood flow in umbilical artery associated with SB

Ethnicity: significant risk factor; »2 times higher in black women than in white women; risk in black women ³1% higher at every maternal age by 30 to 34 yr of age; risk for SB 2.5% in white women 45 to 49 yr of age and in black women 40 to 44 yr of age (sometimes attributed to socioeconomic factors); Vintzileos et al (2002) found excess risk due to higher rates of diabetes mellitus (DM), hypertension (HTN), placental abruption, and prema­ture rupture of membranes among black women

Advanced maternal age: independent risk factor; >40 yr of age; older women more likely to have higher risk forI­UGR; unexplained SB only type more common in older women (tends to occur late in pregnancy)

Obesity: associated additional risk factors (eg, DM, HTN); elevated body mass index (BMI) remains independent risk factor, possibly due to diminsheded perception of decreased fetal movement, vascular disease (caused by hy­perlipidemia) affecting uterus or placenta, or sleep abnormalities (eg, apnea, with potential for oxygen desatura­tion)

Thrombophilias: associated with late fetal death; serial ultrasonography (US), antepartum fetal testing, nonstress testing, and amniotic fluid volume assessment recommended for patient with identified thrombophilia (Doppler assessment if growth restriction identified)

Systemic lupus erythematosus (SLE): strong risk factor, especially with preexisting renal disease; baseline serum creatinine or 24-hr urine collection and laboratory tests for preeclampsia recommended; increased risk even if conception occurred during quiescent period; lupus anticoagulant independently associated with risk for fetal loss at >20 wk gestation; optimum management uncertain; one trial showed anticoagulation with heparin and as­pirin associated with improved outcome

Medical risk factors: HTN and DM historically responsible for large proportion of fetal deaths; medical manage­ment significantly reduces risk; prevalence of no risk factors »80% of pregnancy population; risk in general pop­ulation 4 to 5 per 1000 women; prevalence in women with chronic HTN 6% to 10%, and rate of SB increased to 6 to 25 per 1000 women; risk in women with SLE reported in studies as 4% to as high as 15%; renal disease, thy­roid disease, thrombophilia, cholestasis, tobacco use (10-15 per 1000 women), prepregnancy BMI, and low edu­cational attainment significant risk factors; presence of umbilical cord loop; previous IUGR 12 to 30 per 1000 women; multifetal pregnancies at higher risk; 10% of all women at risk for SB, when taking into account under­lying risk factors

Infection: significant risk factor; little change in trends; associated pathogens include parvovirus, cytomegalovirus, toxoplasmosis, and Listeria monocytogenes; uncertain whether Ureaplasma, Mycoplasma and Group B strepto­cocci significant contributors; preterm birth and postnatal sepsis appear to be contributors; animal data suggest placental infection causes reduction in placental gas exchange (uteroplacental insufficiency and resulting hypoxia)

Infertility: patients who have undergone artificial reproductive technology (ART) have increased perinatal mortal­ity (related to increased rate of mortality in twins and triplets); data support increased risk for adverse outcome in women pregnant with singletons who have undergone in vitro fertilization (IVF) or ovulation induction; with twins, fetal and neonatal death rates plateau at 39 wk; Kahn et al concluded rates of fetal and neonatal death in triplets increase by 36 wk (delivery of triplets at 36 wk gestation recommended)

Biologic markers: minimum maternal hemoglobin concentration ³13.0 g/dL significantly associated with SB (may be result of underlying chronic hypoxia due to lung or cardiac disease); low pregnancy-associated plasma protein A (PAPP-A) level in first trimester; abnormally high mid-trimester alpha-fetoprotein (AFP); high human chori­onic gonadotropin (hCG); low unconjugated estriol; elevated S100B (marker for brain damage); high rate of pre­eclampsia, IUGR, placental abruption, SB, and preterm birth with elevated mid-trimester serum analytes (no accepted guidelines for monitoring); serial US and antepartum fetal surveillance at 32 wk recommended

Prevention: preconception counseling; screen for medical and obstetric risk factors (eg, use of angiotensin-convert­ing enzyme inhibitors, elevated hemoglobin A_1c); counsel patients at risk for genetic abnormality; screen for and treat risk factors; address smoking cessation; identify socioeconomic factors; antepartum fetal testing (especially for women with risk factors [eg, black ethnicity, age ³40 yr, obesity]); delivery; benefits of antepartum fetal testing  —  reduction in IUFD; cons  —logistic overload of antepartum testing centers; cost vs benefit unproven; is­sues with insurance coverage; little supportive evidence of safety and efficacy; vaso previa  —  occurs in »1 in 1000 deliveries; fetal vessels traverse internal os and subject to disruption; older studies suggest neonatal death rate 50% to 100%; seatbelts  —data show pregnant woman has 3% risk of being involved in motor vehicle accident (MVA); study showed women wearing seatbelts did not have increased risk for complications, compared to general popula­tion; those involved in MVA and not wearing seatbelt 2 times more likely to experience excessive maternal bleed­ing and 3 times more likely to experience fetal death

Occiput Posterior or Transverse Position

Brian L. Shaffer, MD, Clinical Instructor, Maternal-Fetal Medicine, Department of Obstetrics, Gynecology, and Reproductive Sciences; University of California, San Francisco, School of Medicine

Diagnosis: consider in patient with labor dystocia in first and second stage of labor; indentation in low pelvis associ­ated with occiput posterior (OP); position check at onset of second stage of labor (usually done with sterile vaginal examination); examine fetal ear with considerable molding; US recommended (studies show US superior to clinical examination in detecting noncephalic presentation)

Incidence: important during second stage to time of delivery; 15% to 20% at onset of labor; prelabor OP or occiput transverse (OT) not indicative of OP or OT at time of birth; data on neonates OP at delivery show two-thirds oc­ciput anterior (OA) at onset of labor; approximately one-third of those OP at onset of labor or induction of labor re­mained OP or OT at delivery; of those OP after 8-cm dilation, only 20% remained in OP position at time of delivery; majority of literature supports 5% prevalence for OP and OT at time of delivery

Risk factors: nonmodifiable  —  pelvic outlet; how shape of pelvis interacts with fetus; maternal age; nulliparity; modifiable  —  obesity; birth weight (>4 kg or postterm pregnancy); data suggest lumbar epidural analgesia associ­ated with OP and OT; because findings inconsistent, speaker does not believe epidural should be withheld

Associated neonatal outcomes: increased risks  —  low Apgar scores; cord umbilical artery gas pH <7; meconium-stained amniotic fluid; neonatal intensive care unit (NICU) admission; composite birth trauma (eg, skull fracture, scalp laceration, clavicle fracture, facial nerve palsy); decreased risk for shoulder dystocia (however, shoulder dys­tocia more likely to result in permanent injury)

Adverse maternal outcomes: prolonged first and second stages of labor (increase in artificial rupture of membranes and use of oxytocin, (eg, Pitocin); increased risk for operative vaginal delivery, third- and fourth-degree lacerations, postpartum hemorrhage, and cesarean delivery

OP or OT at prior delivery: slightly increased risk for recurrence; with cesarean delivery  —  increased risk for unex­plained IUFD, uterine rupture with vaginal birth after cesarean (VBAC), placenta previa and accreta, hysterectomy, and maternal mortality; cesarean delivery  — accounts for almost one-third of all deliveries (2007); 50% increase over last decade; »1 in 4 delivered by primary cesarean delivery; associated with increased maternal morbidity (eg, infection, hemorrhage, bladder injury, deep venous thrombosis); external cephalic version, continuous labor sup­ports, and extending diagnosis of active phase arrest proven to reduce rate of cesarean deliveries

Prevention of OP and OT at delivery: hands and knees position  —  study of women at 37 to 39 wk gestation in­structed to assume hand and knees position for 10 min 2 or 3 times per day showed no effect on OP at delivery; beneficial (but not statistically significant) when position assumed during labor; position associated with relief of backache

Management: no randomized controlled trials and few published observational studies; expectant management  —  reassuring fetal heart rate tracing; adequate pelvis; good expulsive efforts; delivery  —  cesarean or operative vag­inal delivery; rotation (eg, digital, manual, forceps)

Rotation in second stage: most common time of rotation; almost all studies associated with second-stage assess­ment of manual rotation or digital rotation

Prophylactic rotation: potentially helpful with abnormal tracing; need for passive second stage (due to, eg, maternal cardiac condition); poor descent with maternal efforts; rescue rotation  —  after arrest of descent (poor progress); often difficult; pushing with patient-digital rotation  —  “assist” with natural rotation

Rotation in first stage: cautioned against in some textbooks; one study suggested decreased success and increased risk for complications (eg, cord prolapse, cervical laceration); exercise caution if attempted; anecdotal reports of success using digital rotation without increased risks

Manual rotation: Walkowiak (1971)  —  published case series over 10-yr period; »2600 patients with OP; performed rotation, followed immediately by low forceps delivery; <1% morbidity and mortality rates; Israeli study  —showed women managed expectantly less likely to have normal vaginal delivery and more likely to undergo ce­sarean delivery or operative vaginal delivery; women managed expectantly remained OP at delivery »85% of time; of women undergoing trial of rotation, 77% had normal vaginal delivery (6% remained OP at delivery); women in rotation group who had trial of rotation had shorter second stage and shorter hospital stay (likely be­cause of decreased cesarean delivery rate); French study  —  showed rotation in first stage and failure to progress strongest predictors of failure; failure of manual rotation associated with higher cesarean delivery rate than was success (60% vs 4%); University of California San Francisco (UCSF) study  —  trial of manual rotation vs expect­ant management; <10% of women with trial of manual rotation had cesarean delivery, compared to 41% of women who had expectant management; women who underwent trial of manual rotation in second stage of labor delivered faster (even nulliparas); decreased maternal morbidity (postpartum hemorrhage, infection, and third- and fourth-degree lacerations); increased cervical laceration (»2.2% vs 0.9% in those without trial of rotation); improved Apgar score with trial of rotation; potential impact  —  trial of rotation associated with lower risk for ce­sarean delivery; could potentially decrease cesarean deliveries by 55,000 (»2%); may limit neonatal morbidity

Techniques: do not attempt >3 times; limit digital pressure on fetal skull (too much pressure can result in fetal in­jury); associated with cervical laceration; Walkowiak  —left hand to rotate left OP and left OT and right hand to rotate right OP and right OT; Reichman  —  digital method and manual rotation; Tarnier  —  would not perform ro­tation with <7 cm; hybrid  —  with or without push; questions  —  elevate out of pelvis? position of fetal spine? baby’s head deflexed? UCSF approach  —complete dilation; know station and labor curve; confirm with US; know position of fetal spine; digital rotation with push less invasive (can be done with less anesthesia than full manual rotation); abdominal hand helpful in assisting with rotation; if baby returns to OP  —  turn again; if easily accomplished, use forceps and try low operative vaginal delivery

Suggested Reading

Fretts RC: Etiology and prevention of stillbirth. Am J Obstet Gynecol 193:1923, 2005; Fretts RC et al: The changing pattern of fetal death, 1961-1988. Obstet Gynecol 79:35, 1992; Huang DY et al: Determinants of unexplained antepartum fetal deaths. Obstet Gynecol 95:215, 2000; Kiely JL et al: Epidemiological trends in multiple births in the United States, 1971-1998. Twin Res 4:131, 2001; Le Ray C et al: Manual rotation in occiput posterior or transverse positions: risk factors and con­sequences on the cesarean delivery rate. Obstet Gynecol 110:873, 2007; [No authors listed] ACOG practice bulletin. Antepar­tum fetal surveillance. Number 9, October 1999. Clinical management guidelines for obstetrician-gynecologists. Int J Gynaecol Obstet 68:175, 2000; Saade GR et al: Inherited thrombophilia and stillbirth. Semin Perinatol 26:51, 2002; Shaffer BL et al: Manual rotation of the fetal occiput: predictors of success and delivery. Am J Obstet Gynecol 194:e7-9, 2006; Smu­lian JC et al: Twin deliveries in the United States over three decades: an age-period-cohort analysis. Obstet Gynecol 104:278, 2004; Walkowiak RG: Manual rotation of the transverse posterior occiput. Obstet Gynecol 37:464, 1971.