Cervical preparation for second-trimester surgical abortion prior to 20 weeks of gestation

Women-specific routes of administration for drugs: A critical overview

The woman's body presents a number of unique anatomical features that can constitute valuable routes for the administration of drugs, either for local or systemic action. These are associated with genitalia (vaginal, endocervical, intrauterine, intrafallopian and intraovarian routes), changes occurring during pregnancy (extra-amniotic, intra-amniotic and intraplacental routes) and the female breast (breast intraductal route). While the vaginal administration of drug products is common, other routes have limited clinical application and are fairly unknown even for scientists involved in drug delivery science. Understanding the possibilities and limitations of women-specific routes is of key importance for the development of new preventative, diagnostic and therapeutic strategies that will ultimately contribute to the advancement of women's health. This article provides an overview on women-specific routes for the administration of drugs, focusing on aspects such as biological features pertaining to drug delivery, relevance in current clinical practice, available drug dosage forms/delivery systems and administration techniques, as well as recent trends in the field.

Current and potential methods for second trimester abortion

Medical and surgical methods can both be recommended for second trimester abortion (after 12-weeks of gestational age). Induced abortion with a mifepristone and misoprostol regimen is the preferred approach; where mifepristone is not available, misoprostol alone for medical abortion is also effective. Dilation and evacuation (D&E) is the procedure of choice for surgical abortions, and adequate cervical preparation contributes significantly to safety. Availability of drugs and instruments, ability to provide pain control, provider skill and comfort, client preference, cultural considerations, and local legislation all influence the method of abortion likely to be performed in a given setting. Both surgical and modern medical methods are safe and effective when provided by a trained, experienced provider.

Two cervical preparation regimens prior to surgical abortion at 10-14 weeks of gestation: A randomized clinical trial

BACKGROUND

The aim of the study was to determine whether same-day cervical preparation with an osmotic dilator and misoprostol was as effective and safe as overnight cervical preparation for surgical abortions at 10-14 weeks.

METHODS

Seventy women seeking surgical abortion at 10-14 weeks were allocated to receive one osmotic dilator 16-17 h or 6-7 h prior to an abortion. All women received misoprostol 400 μg orally 2 h before the abortion.

RESULTS

The abortion time of the same-day group was 7.42 ± 1.73 min, and that of the overnight group was 8.00 ± 2.19 min (p = 0.23). The blood loss volume of the same-day group was 20.6 ± 10.6 mL, and that of the overnight group was 16.3 ± 7.0 mL (p = 0.55). The degree of cervical dilation for the same-day group was inferior to the overnight group (p = 0.02).

CONCLUSIONS

Same-day cervical preparation with misoprostol and an osmotic dilator shortens the hospitalization days, suggesting same-day cervical preparation is safe, effective, and feasible for surgical abortion at 10-14 weeks of gestation.

Update on second-trimester surgical abortion

PURPOSE OF REVIEW

To review the recent literature on surgical second-trimester abortion, with specific attention to cervical preparation techniques.

RECENT FINDINGS

Confirming previous studies, a recent retrospective observational cohort study, including 54 911 abortions, estimated the total abortion-related complication rate to be 0.41% for second-trimester or later procedures. Cervical preparation is known to reduce risks associated with second-trimester dilation and evacuation (D&E). When considering adjuncts to osmotic dilators for cervical preparation prior to D&E after 16 weeks, both misoprostol and mifepristone are effective alone and in combination or as adjuncts to osmotic dilators. Misoprostol consistently has been shown to cause more pain and cramping than placebo, but is an effective adjunct to osmotic dilators after 16 weeks. Although mifepristone has fewer side-effects, at its current price, it may not be as cost-effective as misoprostol.

SUMMARY

Second-trimester abortion is safe. The use of mifepristone and misoprostol for second-trimester abortion has improved safety and efficacy of medical and surgical methods when used alone or in combination and as adjuncts to osmotic dilators. An important aspect of D&E, cervical preparation, is not a one-size-fits-all practice; the approach and methods are contingent on patient, provider and setting and should consider all the evidence-based options.

Analysis of cervical resistance during continuous controllable balloon dilatation: controlled clinical and experimental study

Background

Hydraulic dilatation is a novel method of cervical dilatation that is based on continuous controllable dilatation (CCBD) by the pumping of fluid into the balloon extension of the system. The main advantage of this procedure is that it allows control of and insight into the process of cervical dilatation.

Methods

For the purposes of our research, we created a new and upgraded system for CCBD which consists of a programmed hydrostatic pump connected to a balloon extension. With regard to our aim to precisely measure and determine the location of the cervical resistance, we placed two pressure-measuring films, one on the top and one on the bottom of the balloon extension. This study included 42 patients in whom cervical resistance was measured before suction curettage.

Results

Cervical dilatation and measurement of cervical resistance were successful in all patients. The analysis of the pressure-measuring films showed that the points of highest resistance were located in the zone of the internal cervical os and that these values were much higher than those in the zone of the external cervical os (0.402 versus 0.264 MPa at the upper pressure-sensitive film; 0.387 versus 0.243 MPa at the lower pressure-sensitive film). This study also showed that an increase in cervical resistance in the zone of the internal cervical os was followed by an increase in cervical resistance in the zone of the external cervical os.

Conclusions

During CCBD, the internal cervical os is the centre of cervical resistance, and the values do not decline with the number of miscarriages or the number of previous births.

Trial registration number

ISRCTN Registry identifier: ISRCTN30949871. Date of registration: 13 May 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-015-1003-8) contains supplementary material, which is available to authorized users.

Prevalence and risk factors of inadequate cervical dilation following laminaria insertion in second-trimester abortion--case control study

OBJECTIVE

The objective was to explore the prevalence of and risk factors for inadequate cervical dilation following insertion of a single set of laminaria in women scheduled for dilation & evacuation (D&E) at 14-24 weeks' gestation.

STUDY DESIGN

We retrospectively reviewed all cases of women who underwent pregnancy termination by D&E at 14-24 weeks' gestation between January 2003 and December 2013. All cases in which the surgical procedure was cancelled due to failure to achieve adequate cervical dilation after a single set of laminaria inadequate cervical dilation were included. The control group was women who underwent D&E following adequate cervical dilation after a single set of laminaria, and were matched according to gestational week in a ratio of 1:3.

RESULTS

The overall dilation failure rate was 3.2%, with 4.0% among the induced-abortion patients and 1.5% among the patients with fetal demise (p=.002). Patients who had inadequate cervical dilation had lower rates of gravidity (p=.002) and previous spontaneous vaginal delivery (p<.001), along with higher rates of primigravidity, nulliparity (p<.001), previous cesarean section/s (p=.041), previous abdominal surgeries (p=.001) and previous cervical procedures (p=.003), compared to controls. A multivariable logistic regression analysis revealed two risk factors for inadequate cervical dilation following laminaria insertion, namely, previous cesarean section (p=.002) and previous cervical procedure (p<.001), whereas increased gravidity was found to protect against inadequate cervical dilation (p=.002).

CONCLUSIONS

Previous cesarean section/s, cervical procedures and primigravidity were found to be risk factors for failure to achieve adequate cervical dilation after a single set of laminaria. Women who are scheduled for D&E, and in whom one of these risk factors exists, might benefit from additional interventions to achieve better cervical preparation.

Intrauterine lidocaine for pain control during laminaria insertion: a randomized controlled trial

OBJECTIVE

To determine if intrauterine administration of 5 cc of 2% lidocaine in addition to paracervical block reduces pain during laminaria insertion, when compared with paracervical block and saline placebo.

STUDY DESIGN

This was a randomized, double blind placebo-controlled trial. Women presenting for abortion by dilation and evacuation (D&E) at 14-24 weeks gestational age were randomized to receive an intrauterine instillation of either 5 mL of 2% lidocaine or 5 mL of normal saline, in addition to standard paracervical block with 20 cc of 0.25% bupivacaine. Our primary outcome was self-reported pain scores on a 100mm Visual Analogue Scale (VAS) immediately following laminaria insertion. Secondary outcome was self-reported VAS pain score indicating the maximum level of pain experienced during the 24-48-h interval between laminaria insertion and D&E procedure.

RESULTS

Seventy-two women were enrolled, and data for 67 women were analyzed, only two of whom were more than 21 weeks on gestation. The range of pain scores at both time points was large (1-90 mm at laminaria insertion; 0-100mm in laminaria-D&E interval). Mean pain scores were not different between treatment groups at laminaria insertion, (33 vs. 32, p=.8) or in the laminaria - D&E interval (43 vs. 44, p=.9).

CONCLUSION

Intrauterine administration of 5 cc of 2% lidocaine in addition to paracervical block did not reduce pain with laminaria insertion when compared to paracervical block with saline placebo.

IMPLICATIONS

Intrauterine lidocaine combined with paracervical block does not improve pain control at laminaria insertion when compared with paracervical block and saline placebo. Wide variation in pain scores and persistent pain after laminaria insertion suggests patient would benefit from more effective methods of pain control at laminaria insertion and during the post-laminaria interval.

Computer simulation of cervical tissue response to a hydraulic dilator device

Background

Classical mechanical dilators for cervical dilation are associated with various complications, such as uterine perforation, cervical laceration, infections and intraperitoneal hemorrhage. A new medical device called continuous controllable balloon dilator (CCBD) was constructed to make a significant reduction in all of the side effects of traditional mechanical dilation.

Method

In this study we investigated numerically the cervical canal tissue response for Hegar and CCBD using our poroelastic finite element model and in-house software development. Boundary conditions for pressure loading on the tissue for both dilators in vivo were measured experimentally. Material properties of the cervical tissue were fitted with experimental in vivo data of pressure and fluid volume or balloon size.

Results

Obtained results for effective stresses inside the cervical tissue clearly showed higher stresses for Hegar dilator during dilation in comparison with our CCBD.

Conclusion

This study opens a new avenue for the implementation of CCBD device instead of mechanical dilators to prevent cervical injury during cervical dilation.

Interruption of nonviable pregnancies of 24-28 weeks' gestation using medical methods: release date June 2013 SFP guideline #20133

The need to interrupt a pregnancy between 24 and 28 weeks of gestation is uncommon and is typically due to fetal demise or lethal anomalies. Nonetheless, treatment options become more limited at these gestations, when access to surgical methods may not be available in many circumstances. The efficacy of misoprostol with or without mifepristone has been well studied in the first and earlier second trimesters of pregnancy, but its use beyond 24 weeks' gestation is less well described. This document attempts to synthesize the existing evidence for the use of misoprostol with or without mifepristone to induce labor for nonviable pregnancies at gestations of 24-28 weeks. The composite evidence suggests that a regimen combining mifepristone and misoprostol may shorten the time to expulsion, though the overall success rates are similar to those seen with misoprostol-only regimens.

Mifepristone vs. osmotic dilator insertion for cervical preparation prior to surgical abortion at 14-16 weeks: a randomized trial

BACKGROUND

Cervical preparation is recommended before second-trimester abortion. We investigated the use of a pharmacologic method of preparation, mifepristone, as compared to osmotic dilators for surgical abortions at 14-16 weeks.

STUDY DESIGN

This was a randomized, parallel-group study with concealed allocation. Women were allocated to receive osmotic dilators or mifepristone 200 mg orally 24 h prior to abortion. The study population was 50 women seeking surgical abortion at 14-16 menstrual weeks in a hospital-based abortion service. The primary outcome was the length of time to perform the procedure; the study had 80% power to detect a difference of more than 3 min in procedure time. Secondary outcomes included cervical dilation, side effects and acceptability.

RESULTS

The mean abortion time for the osmotic dilator group was 8.00 min [95% confidence interval (CI) 6.75-11.47], and that for the mifepristone group was 9.87 min (95% CI 8.93-11.36). Side effects of pain were more common in the osmotic dilator group.

CONCLUSION

Mifepristone did not increase the time for abortion by more than the prespecified margin (3 min). Women preferred mifepristone to osmotic dilators.

Continuous controllable balloon dilation: a novel approach for cervix dilation

Background

Cervical dilation using mechanical dilators is associated with various complications, such as uterine perforation, cervical laceration, infections and intraperitoneal hemorrhage. To achieve safe and painless cervical dilation, we constructed a new medical device to achieve confident mechanical cervical dilation: a continuous controllable balloon dilator (CCBD).

Methods

Controlled pumping of incompressible fluid into the CCBD increases the pressure and outer diameter of the CCBD, continuously dilating the cervical canal. The reliability of the CCBD was confirmed in vitro (testing for consistency and endurance, with no detected risk for breakage) and in vivo. A multi-center clinical study was conducted,with 120 pregnant women randomly assigned to one of three groups: Group I,control group, no dilation;Group II,mechanical dilation, Hegar dilator (HeD); and Group III,CCBD. The tissue material for histological evaluation was obtained from the endocervical mucosa before and after dilation using the HeD or CCBD.

Results

The CCBD dilations were successful and had no complications in all 40 patients of Group III. The cervical tissue was markedly less damaged after CCBD dilation compared with HeD dilation (epithelium damage: 95% (HeD) vs. 45% (CCBD), P <0.001; basal membrane damage: 82.5% (HeD) vs. 27.5% (CCBD), P <0.001; stromal damage: 62.5% (HeD) vs. 37.5% (CCBD), P <0.01). Cervical hemorrhagia was observed in 90% of the patients after HeD dilation versus in 32.5% of the patients after CCBD dilation.

Conclusions

The CCBD should be used as a replacement for mechanical dilators to prevent uterine and cervical injury during cervical dilation.

Trial registration

ISRCTN54007498

Cervical preparation for second trimester dilation and evacuation

BACKGROUND

Abortion during the second trimester of pregnancy accounts for 10-15% of abortions performed worldwide. Dilation and evacuation (D&E) is the preferred method of second-trimester abortion in most parts of the developed world. Cervical preparation is recommended for dilation and curettage (D&C) after 12 weeks gestation and is standard practice for D&E beyond 14 weeks gestation. Prostaglandins, osmotic dilators, and Foley balloon catheters have been used and studied as cervical preparation prior to second-trimester D&E. However, no consensus exists as to which cervical preparation method is superior with regards to safety, procedure time, need for additional dilation, ability to perform the procedure, or patient and provider acceptability. Despite the fact that the advent of osmotic dilation has improved the safety of the D&E procedure during the second trimester, it is unclear whether a certain type of osmotic dilator is superior to another or whether osmotic dilation with adjuvant prostaglandin is superior to osmotic dilation alone or to prostaglandins alone.

OBJECTIVES

This review evaluates cervical preparation methods for second-trimester surgical abortion with respect to differences in procedure time, dilation achieved, need for additional dilation, complications, ability to complete the procedure, patient pain scores, and patient and provider acceptability and satisfaction.

SEARCH STRATEGY

We searched for trials of cervical preparation prior to second-trimester D&E.

SELECTION CRITERIA

We included all randomized controlled trials that compared osmotic, mechanical, antiprogesterone, prostaglandin, or other medical agents of cervical preparation for second-trimester surgical abortion from 14-24 weeks of gestation.

DATA COLLECTION AND ANALYSIS

Data were abstracted by two authors and data entry was verified by a third author. Mean difference and Peto Odds Ratio were calculated.

MAIN RESULTS

Osmotic dilators were found to be superior to prostaglandins with respect to cervical dilation throughout the second trimester and with respect to procedure time within the early second trimester. Addition of prostaglandins to osmotic dilators was not found to increase cervical dilation, except after 19 weeks gestation, however, no impact was seen on procedure time. Addition of Mifepristone to misoprostol was found to improve cervical dilation, yet increase procedure time and frequency of pre-procedural expulsions. Two-day cervical preparation was found to produce greater cervical preparation than one-day, but had no impact on procedure time. Serious complication rates or ability to complete the procedure did not differ significantly between any of the preparation methods reviewed.

AUTHORS' CONCLUSIONS

Cervical preparation with osmotic dilators and/or misoprostol before second-trimester D&E is safe and effective. Osmotic dilators appear to provide superior cervical dilation when compared to prostaglandins alone or when combined with prostaglandins, however this difference in cervical dilation does not appear to result in differences in procedure time or complication rates. There does not appear to be clear clinical benefit from two days of cervical preparation compared to one-day prior to second-trimester D&E below 19 weeks gestational duration. Mifepristone plus misoprostol was associated with high rates of pre-procedural expulsions and does not appear to be a useful method of cervical preparation before second-trimester dilation and evacuation. Same-day procedures appear to be a safe and reasonable option in the early second trimester, however, more research is needed to assess the effectiveness and safety of same-day procedures in the later second trimester.

Cervical preparation with laminaria tents improves induction-to-delivery interval in second- and third-trimester medical termination of pregnancy

BACKGROUND

The purpose of our study was to determine whether cervical preparation with laminaria tents would improve the procedure of second- and third-trimester medical termination of pregnancy (TOP) in terms of duration of abortion and hospitalization.

STUDY

A retrospective comparative study of two historical periods of women undergoing second- and third-trimester medical TOP at a single tertiary care center from September 2004 to December 2006 was conducted. During Period A, patients received oral mifepristone and vaginal misoprostol, while during Period B, laminaria tents were added. Main outcome measures included initiation-to-delivery (ITD) time, induction-to-delivery interval and hospitalization time.

RESULTS

Of 186 eligible women, 174 were enrolled in the study: 91 patients during Period A and 83 patients during Period B. The ITD time was reduced during Period B compared to Period A (43.2+/-6.2 h and 48.5+/-13.2 h, respectively; p=.001). Similarly, the induction-to-delivery interval was significantly shorter during Period B (7.5 h) compared to Period A (12.7 h; p=.001). A significant reduction in total hospital stay was observed during Period B (3 days) versus Period A (4 days; p<.001).

CONCLUSION

Cervical preparation with laminaria tents significantly shortens the duration of medical TOP that uses mifepristone-misoprostol without adverse events or serious complications.