Amnioinfusion

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Amnioinfusion
ICD-9-CM 75.37

Amnioinfusion is a method in which isotonic fluid is instilled into the uterine cavity.

Contents

It was introduced in the 1960s as a means of terminating pregnancy and inducing labor in intrauterine death, but is currently used as a treatment in order to correct fetal heart rate changes caused by umbilical cord compression, indicated by variable decelerations seen on fetal heart rate monitoring. In severe cases of oligohydramnios, amnioinfusion may be performed prophylactically to prevent umbilical cord compression. [1]

It has also been used to reduce the risk of meconium aspiration syndrome, though evidence of benefit is mixed. [2] [3] [4] The UK National Institute of Health and Clinical Excellence (NICE) Guidelines recommend against the use of amnioinfusion in women with meconium stained amniotic fluid (MSAF). [5]

Uses

Diagnostic uses

Diagnostic uses for amnioinfusion are limited to pregnancies complicated by oligohydramnios. Infusion of saline can allow for better visualization of fetal structures on ultrasound when there is minimal amniotic fluid. Most often, it is used to increase the sensitivity of detecting anomalies with the fetus's urogenital tract that could be contributing to the oligohydramnios. Often amnioinfusion isn't needed, as renal agenesis, one of the most common causes of oligohydramnios, is detectable through Doppler ultrasound. [6]

Therapeutic uses

Amnioinfusion is used much more therapeutically in the period just before birth: [6]

Contraindications

Relative contraindications for amnioinfusion include intrauterine infection and maternal immunosuppression to avoid systemic infection, placental abruption and evidence of fetal distress on fetal heart rate monitoring as these are more emergent conditions requiring surgery, and uterine contractions because these make it technically difficult to perform transabdominal amnioinfusion. [6]

Complications

Amnioinfusion can be complicated by premature rupture of membranes, intrauterine infection, maternal pulmonary embolus, puncture and hemorrhage of umbilical cord, precipitous labor, and placental abruption. [6] There are minimal literature addressing incidence rates of these various complications. There are also case reports showing concern for amniotic fluid embolus, [11] polyhydramnios, [12] and malpresentation. [13]

It is recommended that amnioinfusion be performed at centers specializing in fetal medicine and within the context of a multidisciplinary team. [14]

Technique

The most common method of amnioinfusion is the transabdominal approach. The abdomen is generally numbed with local anesthesia and a small needle is inserted into the abdomen, through the uterus, and into the intrauterine cavity. This is performed under ultrasound guidance, often with doppler, to avoid injuring the fetus, placenta, or umbilical cord and aspiration is performed at the time to ensure intra-uterine placement. Warm normal saline is generally used to then increase the amniotic fluid index to over 5 cm.

Amnioinfusion can also be performed transcervically (through the cervix) after the amniotic sac has ruptured. [6]

History

Amnioinfusion was initially performed as a means of achieving first- and second-trimester abortion through the infusion of formalin and hypertonic glucose. [15] Hypertonic saline was first used in the 1960s in the United States to induce labor in patients whose pregnancy ended in intrauterine death. In the 1970s, hypertonic saline overtook other solutions for performing abortions before 14 weeks of gestation. Due to its high risk for infection, hemorrhage, and retained placental tissue leading to a roughly 10% mortality rate, amnioinfusion was largely replaced by prostaglandin medications for performing abortions in the 1980s. It was at this time that medical providers began to use amnioinfusion for other therapeutic purposes. [15] The first report of using isotonic saline or Lactated Ringers solution for repeated late decelerations on fetal heart tracing was in 1983 using either a spinal needle or transcervical catheter. [15] In the following decade, medical providers found more applications, including preventing meconium aspiration syndrome and perinatal death in patients presenting with meconium-stained amniotic fluid, but these applications proved to be not beneficial in the long-run. [16] [17] [18] It was also used for chorioamnionitis, but a Cochrane Review demonstrated its lack of efficacy. [19]

Related Research Articles

<span class="mw-page-title-main">Amniocentesis</span> Sampling of amniotic fluid done mainly to detect fetal chromosomal abnormalities

Amniocentesis is a medical procedure used primarily in the prenatal diagnosis of genetic conditions. It has other uses such as in the assessment of infection and fetal lung maturity. Prenatal diagnostic testing, which includes amniocentesis, is necessary to conclusively diagnose the majority of genetic disorders, with amniocentesis being the gold-standard procedure after 15 weeks' gestation.

<span class="mw-page-title-main">Breech birth</span> Birth of a baby bottom first

A breech birth is when a baby is born bottom first instead of head first, as is normal. Around 3–5% of pregnant women at term have a breech baby. Due to their higher than average rate of possible complications for the baby, breech births are generally considered higher risk. Breech births also occur in many other mammals such as dogs and horses, see veterinary obstetrics.

Fetal distress, also known as non-reassuring fetal status, is a condition during pregnancy or labor in which the fetus shows signs of inadequate oxygenation. Due to its imprecision, the term "fetal distress" has fallen out of use in American obstetrics. The term "non-reassuring fetal status" has largely replaced it. It is characterized by changes in fetal movement, growth, heart rate, and presence of meconium stained fluid.

<span class="mw-page-title-main">Cardiotocography</span> Technical means of recording the fetal heartbeat and the uterine contractions during pregnancy

Cardiotocography (CTG) is a technique used to monitor the fetal heartbeat and the uterine contractions during pregnancy and labour. The machine used to perform the monitoring is called a cardiotocograph.

<span class="mw-page-title-main">Chorionic villus sampling</span> Type of prenatal diagnosis done to determine chromosomal or genetic disorders in the fetus

Chorionic villus sampling (CVS), sometimes called "chorionic villous sampling", is a form of prenatal diagnosis done to determine chromosomal or genetic disorders in the fetus. It entails sampling of the chorionic villus and testing it for chromosomal abnormalities, usually with FISH or PCR. CVS usually takes place at 10–12 weeks' gestation, earlier than amniocentesis or percutaneous umbilical cord blood sampling. It is the preferred technique before 15 weeks.

Oligohydramnios is a medical condition in pregnancy characterized by a deficiency of amniotic fluid, the fluid that surrounds the fetus in the abdomen, in the amniotic sac. It is typically diagnosed by ultrasound when the amniotic fluid index (AFI) measures less than 5 cm or when the single deepest pocket (SDP) of amniotic fluid measures less than 2 cm. Amniotic fluid is necessary to allow for normal fetal movement, lung development, and cushioning from uterine compression. Low amniotic fluid can be attributed to a maternal, fetal, placental or idiopathic cause and can result in poor fetal outcomes including death. The prognosis of the fetus is dependent on the etiology, gestational age at diagnosis, and the severity of the oligohydramnios.

<span class="mw-page-title-main">Amniotic fluid</span> The fluid surrounding a fetus within the amnion

The amniotic fluid is the protective liquid contained by the amniotic sac of a gravid amniote. This fluid serves as a cushion for the growing fetus, but also serves to facilitate the exchange of nutrients, water, and biochemical products between mother and fetus.

<span class="mw-page-title-main">Umbilical cord prolapse</span> Complication of pregnancy where the umbilical cord slips out of the uterus prior to birth

Umbilical cord prolapse is when the umbilical cord comes out of the uterus with or before the presenting part of the baby. The concern with cord prolapse is that pressure on the cord from the baby will compromise blood flow to the baby. It usually occurs during labor but can occur anytime after the rupture of membranes.

<span class="mw-page-title-main">Twin-to-twin transfusion syndrome</span> Medical condition

Twin-to-twin transfusion syndrome (TTTS), also known as feto-fetal transfusion syndrome (FFTS), twin oligohydramnios-polyhydramnios sequence (TOPS) and stuck twin syndrome, is a complication of monochorionic multiple pregnancies in which there is disproportionate blood supply between the fetuses. This leads to unequal levels of amniotic fluid between each fetus and usually leads to death of the undersupplied twin and, without treatment, usually death or a range of birth defects or disabilities for a surviving twin, such as underdeveloped, damaged or missing limbs, digits or organs, especially cerebral palsy.

Potter sequence is the atypical physical appearance of a baby due to oligohydramnios experienced when in the uterus. It includes clubbed feet, pulmonary hypoplasia and cranial anomalies related to the oligohydramnios. Oligohydramnios is the decrease in amniotic fluid volume sufficient to cause deformations in morphogenesis of the baby.

<span class="mw-page-title-main">Placental abruption</span> Medical condition

Placental abruption is when the placenta separates early from the uterus, in other words separates before childbirth. It occurs most commonly around 25 weeks of pregnancy. Symptoms may include vaginal bleeding, lower abdominal pain, and dangerously low blood pressure. Complications for the mother can include disseminated intravascular coagulopathy and kidney failure. Complications for the baby can include fetal distress, low birthweight, preterm delivery, and stillbirth.

<span class="mw-page-title-main">Prelabor rupture of membranes</span> Medical condition

Prelabor rupture of membranes (PROM), previously known as premature rupture of membranes, is breakage of the amniotic sac before the onset of labor. Women usually experience a painless gush or a steady leakage of fluid from the vagina. Complications in the baby may include premature birth, cord compression, and infection. Complications in the mother may include placental abruption and postpartum endometritis.

<span class="mw-page-title-main">Chorioamnionitis</span> Medical condition

Chorioamnionitis, also known as intra-amniotic infection (IAI), is inflammation of the fetal membranes, usually due to bacterial infection. In 2015, a National Institute of Child Health and Human Development Workshop expert panel recommended use of the term "triple I" to address the heterogeneity of this disorder. The term triple I refers to intrauterine infection or inflammation or both and is defined by strict diagnostic criteria, but this terminology has not been commonly adopted although the criteria are used.

Postterm pregnancy is when a woman has not yet delivered her baby after 42 weeks of gestation, two weeks beyond the typical 40-week duration of pregnancy. Postmature births carry risks for both the mother and the baby, including fetal malnutrition, meconium aspiration syndrome, and stillbirths. After the 42nd week of gestation, the placenta, which supplies the baby with nutrients and oxygen from the mother, starts aging and will eventually fail. Postterm pregnancy is a reason to induce labor.

Placental insufficiency or utero-placental insufficiency is the failure of the placenta to deliver sufficient nutrients to the fetus during pregnancy, and is often a result of insufficient blood flow to the placenta. The term is also sometimes used to designate late decelerations of fetal heart rate as measured by cardiotocography or an NST, even if there is no other evidence of reduced blood flow to the placenta, normal uterine blood flow rate being 600mL/min.

<span class="mw-page-title-main">Velamentous cord insertion</span> Velamentous placenta

Velamentous cord insertion is a complication of pregnancy where the umbilical cord is inserted in the fetal membranes. It is a major cause of antepartum hemorrhage that leads to loss of fetal blood and associated with high perinatal mortality. In normal pregnancies, the umbilical cord inserts into the middle of the placental mass and is completely encased by the amniotic sac. The vessels are hence normally protected by Wharton's jelly, which prevents rupture during pregnancy and labor. In velamentous cord insertion, the vessels of the umbilical cord are improperly inserted in the chorioamniotic membrane, and hence the vessels traverse between the amnion and the chorion towards the placenta. Without Wharton's jelly protecting the vessels, the exposed vessels are susceptible to compression and rupture.

An obstetric labor complication is a difficulty or abnormality that arises during the process of labor or delivery.

<span class="mw-page-title-main">Circumvallate placenta</span> Medical condition

Circumvallate placenta is a rare condition affecting about 1-2% of pregnancies, in which the amnion and chorion fetal membranes essentially "double back" on the fetal side around the edges of the placenta. After delivery, a circumvallate placenta has a thick ring of membranes on its fetal surface. Circumvallate placenta is a placental morphological abnormality associated with increased fetal morbidity and mortality due to the restricted availability of nutrients and oxygen to the developing fetus.

Artificial rupture of membranes (AROM), also known as an amniotomy, is performed by a midwife or obstetrician and was once thought to be an effective means to induce or accelerate labor. The membranes can be ruptured using a specialized tool, such as an amnihook or amnicot, or they may be ruptured by the proceduralist's finger. The different techniques for artificial rupture of membranes have not been extensively compared in the literature. In one study comparing amnihook versus amnicot for artificial rupture of membranes, use of an amnicot was associated with fewer neonatal scalp lacerations.

Uterine Tachysystole is a condition of excessively frequent uterine contractions during pregnancy. It is most often seen in induced or augmented labor, though it can also occur during spontaneous labor, and this may result in fetal hypoxia and acidosis. This may have serious effects on both the mother and the fetus including hemorrhaging and death. There are still major gaps in understanding treatment as well as clinical outcomes of this condition. Uterine tachysystole is defined as more than 5 contractions in 10 minutes, averaged over a 30-minute period.

References

  1. ↑ Hsu TL, Hsu TY, Tsai CC, Ou CY (December 2007). "The experience of amnioinfusion for oligohydramnios during the early second trimester". Taiwanese Journal of Obstetrics & Gynecology. 46 (4): 395–398. doi: 10.1016/S1028-4559(08)60009-1 . PMID   18182345.
  2. ↑ Fraser WD, Hofmeyr J, Lede R, Faron G, Alexander S, Goffinet F, et al. (September 2005). "Amnioinfusion for the prevention of the meconium aspiration syndrome". The New England Journal of Medicine. 353 (9): 909–917. doi:10.1056/NEJMoa050223. PMID   16135835.
  3. ↑ Edwards RK, Duff P (1999). "Prophylactic cefazolin in amnioinfusions administered for meconium-stained amniotic fluid". Infectious Diseases in Obstetrics and Gynecology. 7 (3): 153–157. doi: 10.1155/S1064744999000241 . PMC   1784731 . PMID   10371474.
  4. ↑ Buckley A, Middleton MC (1987). "Retinoic acid alters the keratinization of cultured rat sublingual keratinocytes in vitro". Archives of Dermatological Research. 279 (4): 257–65. doi:10.1007/BF00417325. PMID   2445304. S2CID   11942931.
  5. ↑ Saygin D, Tabib T, Bittar HE, Valenzi E, Sembrat J, Chan SY, et al. (December 2012). "Transcriptional profiling of lung cell populations in idiopathic pulmonary arterial hypertension". Pulmonary Circulation. 10 (1): 532–535. doi:10.1016/j.paed.2012.08.015. PMC   7052475 . PMID   32166015.
  6. 1 2 3 4 5 Dad N, Abushama M, Konje JC, Ahmed B (September 2016). "What is the role of amnioinfusion in modern day obstetrics?". The Journal of Maternal-Fetal & Neonatal Medicine. 29 (17): 2823–2827. doi:10.3109/14767058.2015.1105953. PMID   26461043. S2CID   30353711.
  7. ↑ "Safe Prevention of the Primary Cesarean Delivery". www.acog.org. Retrieved 2022-12-13.
  8. ↑ Hofmeyr GJ, Lawrie TA, et al. (Cochrane Pregnancy and Childbirth Group) (January 2012). "Amnioinfusion for potential or suspected umbilical cord compression in labour". The Cochrane Database of Systematic Reviews. 1 (1): CD000013. doi:10.1002/14651858.CD000013.pub2. PMC   7061253 . PMID   22258939.
  9. ↑ Esaki M, Maseki Y, Tezuka A, Furuhashi M (April 2020). "Continuous amnioinfusion in women with PPROM at periviable gestational ages". The Journal of Maternal-Fetal & Neonatal Medicine. 33 (7): 1151–1156. doi:10.1080/14767058.2018.1517307. PMID   30149736. S2CID   52096709.
  10. ↑ Hofmeyr GJ, Eke AC, Lawrie TA, et al. (Cochrane Pregnancy and Childbirth Group) (March 2014). "Amnioinfusion for third trimester preterm premature rupture of membranes". The Cochrane Database of Systematic Reviews. 2014 (3): CD000942. doi:10.1002/14651858.CD000942.pub3. PMC   7061243 . PMID   24683009.
  11. ↑ Maher JE, Wenstrom KD, Hauth JC, Meis PJ (May 1994). "Amniotic fluid embolism after saline amnioinfusion: two cases and review of the literature". Obstetrics and Gynecology. 83 (5 Pt 2): 851–854. PMID   8159374.
  12. ↑ Tabor BL, Maier JA (January 1987). "Polyhydramnios and elevated intrauterine pressure during amnioinfusion". American Journal of Obstetrics and Gynecology. 156 (1): 130–1. doi:10.1016/0002-9378(87)90222-5. PMID   3541615.
  13. ↑ Washburne JF, Chauhan SP, Magann EF, Moore JL, Morrison JC (July 1998). "Amnioinfusion-induced malpresentation". Journal of the Mississippi State Medical Association. 39 (7): 240–241. PMID   9670704.
  14. ↑ "Oligohydramnios". Archived from the original on 2016-09-20. at the National Institute for Health and Clinical Excellence. Based on the overview "Therapeutic amnioinfusion for oligohydramnios during pregnancy (excluding labour)" (PDF). Archived from the original (PDF) on 2013-02-18. in 2006
  15. 1 2 3 Contro E, Jauniaux E (January 2021). "Amnioinfusion: from termination of pregnancy to therapy". BJOG. 128 (2): 303. doi:10.1111/1471-0528.16484. PMID   33051973. S2CID   222353733.
  16. ↑ "Overview | Therapeutic amnioinfusion for oligohydramnios during pregnancy (excluding labour) | Guidance | NICE". www.nice.org.uk. Retrieved 2022-12-07.
  17. ↑ Reuter S, Moser C, Baack M (October 2014). "Respiratory distress in the newborn". Pediatrics in Review. 35 (10): 417–28, quiz 429. doi:10.1542/pir.35.10.417. PMC   4533247 . PMID   25274969.
  18. ↑ Hofmeyr GJ, Xu H, Eke AC, et al. (Cochrane Pregnancy and Childbirth Group) (January 2014). "Amnioinfusion for meconium-stained liquor in labour". The Cochrane Database of Systematic Reviews. 2014 (1): CD000014. doi:10.1002/14651858.CD000014.pub4. PMC   7263444 . PMID   24453049.
  19. ↑ Hofmeyr GJ, Kiiza JA, et al. (Cochrane Pregnancy and Childbirth Group) (August 2016). "Amnioinfusion for chorioamnionitis". The Cochrane Database of Systematic Reviews. 2016 (8): CD011622. doi:10.1002/14651858.CD011622.pub2. PMC   6507500 . PMID   27556818.
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