*Division of Maternal Fetal Medicine, North Shore University Hospital/ Cornell Univ. Medical College 300 Community Drive Manhasset, New York 11030-3876 Ph: 516-562-2892 Fax: 516-562-4301. Dept. of Neurology Ph: 516-562-4301 Fax: 516-562-2635

MESH Amniocentesis ICD9 75.100

Introduction

Amniocentesis is considered to be a relatively safe procedure. Complications occurring after the procedure in 1% - 2% of cases (amniotic fluid leakage, contractions) are usually self-limited.

The safety of amniocentesis at 15 weeks of pregnancy or later has been assessed by several collaborative multi-center studies. In the United States, an NICHD-sponsored investigation revealed that 3.5% of pregnant women who underwent amniocentesis during the years 1972 to 1975 experienced fetal loss after the procedure, a rate which did not differ significantly from that of controls (3.2%) who did not undergo amniocenteses ^l,2.

A British collaborative study in the same period (1973-1976) found that the rate of fetal loss following amniocentesis was significantly greater than in controls (2.6% vs. 1%)³. This result was supported by a Danish study in which the fetal loss rate was 1.7% in patients undergoing amniocentesis versus 0.7% in a control group (p<<0.05)⁴. It is important to note that in neither of these collaborative studies was simultaneous ultrasound guidance used.

Direct fetal injuries during an amniocentesis

Though direct fetal injury from the amniocentesis needle is very uncommon, especially since the advent of ultrasound guidance, such injuries may be associated with sequelae. Fetal head and neck, face, thorax and umbilical cord injuries have all been reported.

Table 1 reflects the nature and outcome of fetal injuries during amniocentesis reported in the literature. Only case reports containing information on the gestational age, type and circumstances of injury, as well as fetal and neonatal outcome, were included in this review.

Table 1: Fetal injuries during diagnostic amniocentesis.

Case report

A 36-year-old white patient G₃P_l, underwent genetic amniocentesis at 17 weeks of pregnancy at an outside university hospital. Fetal intracranial, thoracic, and abdominal anatomy assessed during ultrasound examination prior to the amniocentesis appeared normal. The placenta was in a left lateral position,  and the amount of amniotic fluid was normal. The largest pocket of amniotic fluid was in close proximity to the fetal head and neck (fig 1). A 20-gauge spinal needle was inserted into this pocket of amniotic fluid under continuous sonographic guidance using a free-hand technique. Twenty ml of blood-tinged amniotic fluid were obtained and sent for karyotyping. Marked fetal skin thickening measuring approximately 15 mm developed immediately after the procedure was in transverse section at the level of the fetal neck and most likely represented a hemorrhagic collection. In view of the very rapid onset of the skin thickening, a puncture of one or more fetal neck vessels including jugular vein with subsequent neck hematoma formation was considered likely (fig. 2). Follow-up ultrasound examinations at 20 and 26 weeks of pregnancy demonstrated total resolution of the hematoma and normal appearance of the neck (fig. 3). The fetus demonstrated adequate activity,  and the amount of amniotic fluid was normal. Signs of fetal hydrops, placentomegaly, or polyhydramnios as a result of anemia due to presumed blood loss never developed in this fetus.

Figure 1: Normal head prior to the amniocentesis.

Figure 2:  Marked thickening of the subcutaneous tissue around the

Figure 3: Total resolution of the previous findings shown on Fig

Discussion

Most researchers have concluded that fetal puncture during  amniocentesis rarely occurs, and when it does it is of little or no significance^9,14. Most fetal injuries occur during amniocentesis performed in late the 2^nd and 3^rd trimesters of pregnancy. Petrikovsky and Kaplan¹⁵ reported a 0.4 incidence of inadvertent contact between the needle and fetal parts during genetic amniocentesis performed under constant sonographic guidance. Fetal feet and hands were involved in the needle contact more often than fetal head, chest or abdomen.

The immediate response of the fetus consisted of brisk withdrawal of the "involved†small part. None of the newborns exhibited needle marks upon delivery.

More serious complications occur when the fetal head, chest, abdomen or umbilical cord become the targets of inadvertent needle injury. The current case involved a vascular injury of the fetal neck during amniocentesis. Serial ultrasound examinations allowed us to observe an in utero healing process including complete resolution of a large neck hematoma.

Conclusions

Inadvertent contact between an amniocentesis needle and fetal parts occurs infrequently. Serious complications occur mostly during late 2^nd and 3^rd trimester amniocentesis and may cause fetal demise or serious injury. Continuous ultrasound guidance during the procedure, as judged by our experience, cannot guarantee the absolute safety of the fetus; however, simultaneous sonographic guidance is probably responsible for the occurrence of serious fetal injuries as most cases of fetal injuries, were reported prior to its widespread use. There is no apparent association between the needle gauge and the occurrence of severe fetal injury. Fetal vascular injuries rarely occur and may heal spontaneously.

References

1.NICHD Consensus Conference on Antenatal Diagnosis. 1979; NIH publication No. 80-1973, December.

2.NICHD National Registry for Amniocentesis Study Group: Mid­trimester amniocentesis for prenatal diagnosis: Safety and accuracy. JAMA 1976;236:1471.

3.Working Party of Amniocentesis: An assessment of the hazards of amniocentesis. Br J Obstet Gynecol 1978;85 (Suppl 2):l.

4.Tabor A, Madsen M, Obel E, et al: Randomized controlled trial of genetic amniocentesis in 4606 low-risk women. Lancet 1968;1:1287.

5.Wiltchik SG, Schwatz RH, Emich JD. Amniography for placental localization. Obstet Gynecol 1966;28:641-45.

6.Creasman WT, Lawrence RA, Thiede HA. Fetal complications of amniocentesis. JAMA 1968;204:11.

7.Cross HE, Maumenee AE. Ocular trauma during amniocentesis. N Engl J Med 1972;287:993.

8.Hyman CJ, Depp R, Pakravan P, et al: Pneumothorax complicating amniocentesis. Obstet Gynecol 1973;41:43-46.

9.Cook LN, Shott RJ, Andrews BF. Fetal complications of diagnostic amniocentesis: A review and report of a case with pneumothorax. Pediatrics 1974;53:421-23.

10.Egley CC. Laceration of fetal spleen during amniocentesis. Am J Obstet Gynecol 1990;3:107-8.

11. Alvery JP. Obstetrical management of Rh incompatibility based on liquor amnio studies. Am J  Obstet Gynecol 1964;90:769-75.

12.McLain CR. Amniography, a versalite diagnosis procedure in obstetrics. Obstet Gynecol 1969;23:45-50.

13.Ryan GT, Ivy R, Pearson JW. Fetal bleeding as a major hazard of amniocentesis. Obstet Gynecol 1972;40:702-7.

14.Burnett RG, Anderson WR. The hazards of amniocentesis.. J Iowa Med Soc 1968;58:130.

15.Petrikovsky BM, Kaplan GP. Fetal responses to inadvertent contact with the needle during an amniocentesis. In Press.