**4.1 Forceps**

Obstetric forceps can be classified based on the depth of the pelvic cavity in which they can be applied to effect delivery (low/outlet, midcavity or high foceps). Worldwide low cavity and outlet forceps delivery are the mostly frequently performed in current practice. High and mid-cavity forceps delivery which could involve rotation of the fetal head are rarely perfomed. At the Ahmadu Bello University Teaching Hospital, only outlet forceps are performed with low-cavity forceps used occasionally (Adaji et al., 2009).

Fig. 3. The common types of obstetric forceps

Fig. 4. (a-f) – Application and traction on the fetal head using forceps

### **4.2 Vacuum extractor**

258 From Preconception to Postpartum

Obstetric forceps can be classified based on the depth of the pelvic cavity in which they can be applied to effect delivery (low/outlet, midcavity or high foceps). Worldwide low cavity and outlet forceps delivery are the mostly frequently performed in current practice. High and mid-cavity forceps delivery which could involve rotation of the fetal head are rarely perfomed. At the Ahmadu Bello University Teaching Hospital, only outlet forceps are

(a)Wrigley's (b) Simpson's (c) Kielland's (d) Neville-Barnes-Simpson's

Fig. 3. The common types of obstetric forceps

performed with low-cavity forceps used occasionally (Adaji et al., 2009).

**4. Types of equipment** 

**4.1 Forceps** 

There are different types of vacuum extractors, depending on the type of suction mechanism (manual or electrical) and type of cup-rigid or soft (Silc, Malmstrom, Bird, or the OmniCup). The manual suction mechanism which is suitable for resource poor settings due to frequent power outages may be operated via a foot pump, a hand held "bicycle like" pump both operated by an assistant or a hand held pump operated by the birth attendant (Figure 2). The most common and widely available in resource poor settings is the Malmstrom vacuum extractor with rigid or soft cups. both

Fig. 5. Vacuum extractor soft cups (i) and the Kiwi Omnicup (ii) which has a rigid plastic cup

Operative Vaginal Deliveries in Contemporary Obstetric Practice 261

Operative vaginal delivery prevalence rates vary from country from country and facility to facility. The rates have however remained fairly stable over the past 3 decades. A recent survey by the World Health Organization (WHO) of method of delivery and pregnancy outcomes in 9 Asian countries analyzed 107, 950 births. Of these births, 3.2 percent were by

Demissie et al comprehensively reviewed operative vaginal delivery rates in US hospitals between 1995 and 1998. Obstetrical forceps were utilized to conduct deliveries in 4.4% of births in 1995, 4% in 1996, 3.6% in 1997 and 3.2% in 1998. The use of ventouse was 7.4%, 7.8%, 7.8% and 7.6% over the same period (Demissie et al., 2004). In the UK, a operative vaginal delivery rates (forceps and ventouse) of between 10 to 15% percent has been

Due to weak health systems, national figures for instrumental vaginal deliveries are either unavailable or incomplete from developing countries. Reports from comprehensive emergency obstetric health care facilities may provide the most reliable source of information in such settings. For example, a 5 year review of births at the Ahmadu Bello University Teaching Hospital, Zaria revealed that of 6662 vaginal births between 1997 and 2001, 3.9% were by operative vaginal delivery procedures. Forceps delivery rate was 2.2% while vacuum delivery rate was 1.5%. In addition, fetal destructive operation to deliver confirmed intrauterine fetal deaths was employed in 0.1% of cases (Adaji et al., 2009). This procedure is rarely reported in literature from developed countries suggesting that they are no longer performed. However, in developing countries where moribund mothers, neglected obstructed labour and intrauterine fetal deaths are still seen, fetal destructive operation remains an option [Moody & Maharaj 2002]. Table 1 below shows the situation of

operative vaginal procedures based on hospital-based studies in selected countries.

**Country No of births Year of births Vacuum (%) Forceps (%) All** 

USA 4,316,233 2007 3.5 0.8 4.3%

England 515,214 2004 7 3 10%

Canada 333,974 2005 10.3 4.6 14.9%

Australia 289,946 2007 7.5 3.6 11.1%

Ireland 71,963 2007 12.3 3.7 16%

Assisted vaginal delivery is one of the underutilized and least available emergency obstetric care signal functions in resource poor countries (Kongnyuy et al., 2008, Tsu and Coffe, 2009). Unmet training needs, lack of suitable equipment and human resource shortages are some reasons for this (Bailey, 2005, Fauveau, 2006, Hillier and Johanson, 1994). In many resource poor settings vacuum extraction is performed only by medical doctors who may only be

Table 1. Operative vaginal deliveries in 5 countries(Gei and Pacheco, 2011)

regularly available in large urban hospitals (Fauveau, 2006).

operative vaginal delivery procedures (Lumbiganon et al., 2010).

**5. Epidemiology** 

estimated (Johanson and Jones, 1999).

A more recent design for the vacuum extractor is the rigid plastic cup Kiwi® vacuum assisted fetal delivery device (Clinical Innovations, Murray, UT). It is designed as an integrated unit for complete control without an assistant. The suction for this device is provided by a PalmPumpTM. The Kiwi has two versions; the ProCup® for low outlet delivery occipito-posterior positions and the OmniCup® for low occipito-posterio asynclitic and lateral fetal malpositions. The OmniCup® has a disposable and a recently developed reusable version suitable for resource poor settings. The cost, portability and ease of maintenance of the reusable OmniCup® makes it attractive for use in resource poor settings. The disposable version on the other hand reduces the potential risk of viral infections between patients (Ismail et al., 2008a).

Metal cups appear to be more suitable for 'occipito-posterior', transverse and difficult 'occipito-anterior' position deliveries because they allow a greater traction force to be applied without cup slip offs. The soft cups seem to be appropriate for straightforward deliveries (Johanson and Menon, 2007).

Several studies have evaluated the effectiveness of the OmniCup compared to the standard vacuum extraction equipment (Malstrom metal rigid cup or Silc cups). Two randomized controlled trials found a higher failure rate: 43% vs. 21% (OR = 1.9; 95%CI = 1.01 – 1.36) (Attilakos et al., 2006) and 30%-19.2%, (RR 1.58; 95% CI = 1.10-2.224) with the OmniCup and one RCT found it to be a suitable alternative to the standard cups (100% delivery rate in both groups) (Ismail et al., 2008b). There was no difference in maternal morbidity between both groups in all 3 RCTs. Only one of the RCTs reported a significant increase in neonatal admission for sub-aponeurotic hemorrhage (p = 0.015, OR = 0.11; 95CI = 0.001 - 0.87). 

Fig. 6. (a-c) – Position of cup and direction of traction with vacuum extractor

Several observational studies also reported higher rates of successful vaginal delivery which was not statistically different from that for the standard equipment (Ismail et al., 2008a, Hayman et al., 2002, Baskett et al., 2008). Successful vaginal delivery was attributed to familiarity with the equipment. There was also no difference in maternal morbidity in all of these studies. However, Hayman, Gilby and Arulkumaran (2002) reported a significant increase in superficial scalp abrasions in the OmniCup group compared to the standard cup group (Hayman et al., 2002).

The experience from many centers is that nulliparous women with untested pelvis are more likely to need assistance with an operative vaginal delivery procedure. In the Zaria study, more than three-quarters of the parturients who were assisted were nulliparas (Adaji et al., 2009).
