Ultrasound for fetal assessment in early pregnancy.
BACKGROUND
Diagnostic ultrasound is a sophisticated electronic technology, which utilises pulses of high frequency sound to produce an image. Diagnostic ultrasound examination may be employed in a variety of specific circumstances during pregnancy such as after clinical complications, or where there are concerns about fetal growth. Because adverse outcomes may also occur in pregnancies without clear risk factors, assumptions have been made that routine ultrasound in all pregnancies will prove beneficial by enabling earlier detection and improved management of pregnancy complications. Routine screening may be planned for early pregnancy, late gestation, or both. The focus of this review is routine early pregnancy ultrasound.


OBJECTIVE
To assess whether routine early pregnancy ultrasound for fetal assessment (i.e. its use as a screening technique) influences the diagnosis of fetal malformations, multiple pregnancies, the rate of clinical interventions, and the incidence of adverse fetal outcome when compared with the selective use of early pregnancy ultrasound (for specific indications).


METHODS
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (September 2009).


METHODS
Published, unpublished, and ongoing randomised controlled trials that compared outcomes in women who experienced routine versus selective early pregnancy ultrasound (i.e. less than 24 weeks' gestation). We have included quasi-randomised trials.


METHODS
Two review authors independently extracted data for each included study. We used the Review Manager software to enter and analyse data.


RESULTS
Routine/revealed ultrasound versus selective ultrasound/concealed: 11 trials including 37505 women. Ultrasound for fetal assessment in early pregnancy reduces the failure to detect multiple pregnancy by 24 weeks' gestation (risk ratio (RR) 0.07, 95% confidence interval (CI) 0.03 to 0.17). Routine scan is associated with a reduction in inductions of labour for 'post term' pregnancy (RR 0.59, 95% CI 0.42 to 0.83). Routine scans do not seem to be associated with reductions in adverse outcomes for babies or in health service use by mothers and babies. Long-term follow up of children exposed to scan in utero does not indicate that scans have a detrimental effect on children's physical or cognitive development.


CONCLUSIONS
Early ultrasound improves the early detection of multiple pregnancies and improved gestational dating may result in fewer inductions for post maturity. Caution needs to be exercised in interpreting the results of aspects of this review in view of the fact that there is considerable variability in both the timing and the number of scans women received.
Whitworth
Melissa
M
St Mary's Hospital, Central Manchester and Manchester Children's University Hospitals NHS Trust, Hathersage Road, Manchester, UK, M13 0JH.
Bricker
Leanne
L
Neilson
James P
JP
Dowswell
Therese
T
D000013:Congenital Abnormalities / Q000000981:diagnostic imaging; D005260:Female; D005323:Fetal Monitoring / Q000379:methods*; D005865:Gestational Age; D006801:Humans; D054238:Perinatal Mortality; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D011272:Pregnancy, Multiple; D016216:Ultrasonography, Prenatal / Q000379:methods*
Br J Obstet Gynaecol. 1996 Jun;103(6):501-7
8645639
Acta Obstet Gynecol Scand. 1995 Jan;74(1):12-4
7856426
Ultrasound Obstet Gynecol. 2008 May;31(5):579-87
18412093
Ultrasound Obstet Gynecol. 1993 Jan 1;3(1):6-10
12796894
Early Hum Dev. 1992 Aug;30(1):75-9
1396292
Early Hum Dev. 1998 Jan 9;50(2):233-45
9483394
Lancet. 1984 Jul 28;2(8396):207-11
6146762
BJOG. 2002 Jan;109(1):44-56
11843373
Health Technol Assess. 2000;4(16):i-vi, 1-193
11070816
Ultrasound Obstet Gynecol. 2006 Sep;28(3):249-54
16909403
Am J Obstet Gynecol. 1995 Jan;172(1 Pt 1):156-62
7847528
Br J Obstet Gynaecol. 1982 May;89(5):338-41
6805497
Midwifery. 2007 Mar;23(1):13-22
17011088
BJOG. 2006 Jun;113(6):664-74
16709209
Br J Obstet Gynaecol. 1996 Jan;103(1):60-9
8608100
BJOG. 2006 Feb;113(2):171-6
16411994
Am J Obstet Gynecol. 1994 Aug;171(2):392-9
8059817
Am J Obstet Gynecol. 2004 Apr;190(4):1077-81
15118645
Br J Obstet Gynaecol. 1991 Jan;98(1):108-9
1998620
Am J Obstet Gynecol. 1983 Aug 15;146(8):942-7
6881228
Ultrasound Obstet Gynecol. 2009 Sep;34(3):297-303
19705400
Am J Obstet Gynecol. 1993 Sep;169(3):483-9
8372849
Int J Gynaecol Obstet. 2007 Sep;98(3):257-8
17466301
Br J Obstet Gynaecol. 1999 Dec;106(12):1273-9
10609721
Cochrane Database Syst Rev. 2008 Oct 08;(4):CD001451
18843617
BJOG. 2006 Jun;113(6):675-82
16709210
N Engl J Med. 1993 Sep 16;329(12):821-7
8355740
Am J Obstet Gynecol. 1991 Oct;165(4 Pt 1):1002-5
1951502
Ultrasound Obstet Gynecol. 1999 Aug;14(2):92-7
10492867
Obstet Gynecol. 1998 May;91(5 Pt 1):750-6
9572224
Aust N Z J Obstet Gynaecol. 1994 May;34(2):140-3
7980300
Ultrasound Obstet Gynecol. 2002 Aug;20(2):154-62
12153666
Br J Obstet Gynaecol. 1997 Nov;104(11):1267-72
9386027
Ultrasound Obstet Gynecol. 2000 Jun;15(6):473-8
11005114
Obstet Gynecol. 1990 Aug;76(2):189-94
2196496
Acta Obstet Gynecol Scand. 2004 Jul;83(7):634-40
15225187
Lancet. 1984 Jun 16;1(8390):1347
6145038
Ultrasound Obstet Gynecol. 2005 May;25(5):468-72
15849804
Lancet. 1992 Jan 11;339(8785):85-9
1345870
Am J Obstet Gynecol. 2006 Sep;195(3):863-7
16949427
Ultrasound Obstet Gynecol. 1992 Jul 1;2(4):243-4, 245-7
12796948
J Perinat Med. 1994;22(4):279-89
7877064
Birth. 2002 Dec;29(4):225-50
12431263
BMJ. 1993 Jul 17;307(6897):159-64
7688253
Ultrasound Obstet Gynecol. 2004 Jul;24(1):42-50
15229915
Aust N Z J Obstet Gynaecol. 1993 Nov;33(4):374-8
8179545
Lancet. 1990 Aug 18;336(8712):387-91
1974940
Arch Fam Med. 1995 Feb;4(2):120-3
7842149
Lancet. 1988 Sep 10;2(8611):585-8
2900977
Cochrane Database Syst Rev. 2009 Jul 08;(3):CD007235
19588421
Best Pract Res Clin Obstet Gynaecol. 2005 Feb;19(1):131-53
15749071
Br J Psychol. 2005 Feb;96(Pt 1):129-37
15826328
Ultrasound Obstet Gynecol. 1996 May;7(5):309-14
8774094
Ultrasound Obstet Gynecol. 2008 Feb;31(2):136-46; discussion 146
18254132
Lancet. 1998 Jul 4;352(9121):5-6
9800735
Ultrasound Obstet Gynecol. 2005 Jun;25(6):537-45
15912479
Br J Obstet Gynaecol. 1992 Jun;99(6):469-74
1637761