*   Ultrasound Division, ASL Roma B, Rome, Italy.
** Ultrasound Division, Ceprano Hospital, Ceprano, Italy.

Introduction

Synechiae is a term which means "adhesions" or a fibrous scars. Intrauterine adhesions resulting from the uterine trauma, such as curretage, are called Asherman syndrome. They may also result from other uterine interventions such as caesarian section and myomectomy. They rarely result from uterine infections such as chlamydia, tuberculosis, and schistosomiasis and the presence of the foreign body. However, it is not unusual to meet patients with synechiae with lack of any previous relevant history.
This condition usually leads to amenorrhea, hypomenorrhea, habitual abortion and secondary infertility.

Uterine synechiae in pregnancy have also been referred to as "amniotic sheets" or "amniotic folds". They are most commonly noted as an incidental finding during the ultrasound examination in pregnancy.
In general, synechiae do not interfere with the development or fetal growth, and are rarely associated with any complications.

Ultrasound diagnosis

Synechiae appear as thick bands connected to the uterine wall. In other words, a synechia has it's base and a free edge.
In pregnancy, this appearance is caused by a combination of the fibrous synechia itself, and the complete wrapping of fetal membranes around the synechia.

Color Doppler shows blood flow in the majority of synechial bands.

Case 1

A 58-years-old postmenopausal woman who underwent a curettage for menorrhagia. There are synechiae visible because of the fluid present within the uterine cavity.

Images 1,2: Transvaginal ultrasound; arrow indicates synechiea in the uterine cavity.

Case 2

This is a case of a first trimester pregnancy (CRL 10 mm; 7 weeks) of a 32-year-old woman with history of previous dilation and curettage post an early fetal demise. The patient was lost to follow up and the pregnancy outcome is unknown.

Images 3-6: Transvaginal ultrasound images show a gestation sac with embryo, arrow indicates synechiae.

Case 3 and 4

These are incidental findigs in the third trimester (32 and 33 weeks) of pregnancy in women with a history of previous dilation and curettage after an early fetal demise. The pregnancy was uneventful in both cases. Color Doppler was used to show vascularization of the amniotic fold.

Images 7-10: Amniotic folds, Doppler imaging demonstrates vascularization.

References:

1. Necas M, Worrall JA, DuBose TJ. Recognizing Intra-amniotic Band-like Structures on Obstetric Ultrasound; OBGYN.net September 1999
2. Randel SB, Filly RA, Callen PW, Anderson RL, Golbus MS: Amniotic Sheets. Radiology 1988;166(3):633-6.
3. Nyberg DA, Mahony BS, Pretorius DH: Diagnostic Ultrasound of Fetal Anomalies: text and atlas. Mosby-Year Book Inc, 1990:649.
4. Wehbeh H, Felisher J, Karimi A, Mathony A, Minkoff H: The relationship between the ultrasonographic diagnosis of innocent amniotic band development and pregnancy outcomes. Obstet Gynecol 1993;81(4):565-8.
5. Finberg HJ: Uterine synechiae in pregnancy: expanded criteria for recognition and clinical significance in 28 cases. J Ultrasound Med 1991;10(10):547-55.
6. Callen PW: Ultrasonography in Obstetrics and Gynecology. W.B. Saunders Co, 1994:382-386, 445.