For pain relief during a first trimester surgical aspiration, most providers use the paracervical block, either alone or in combination with other pain control techniques. Some providers use buffered lidocaine due to a belief that it decreases pain. Others use plain lidocaine. At our clinics, the standard pain management protocol is using 20 cc of 1% plain lidocaine in a two site injection. Few studies have compared buffered versus unbuffered lidocaine for paracervical blocks during first trimester uterine aspirations. This study seeks to determine if buffered lidocaine decreases injection pain versus plain lidocaine for paracervical blocks.

Potential participants will be identified at their office visits to the University Women's Health Specialists. If a patient desires uterine aspiration of a first trimester pregnancy or management of a failed pregnancy in the first trimester, they will first receive standard counseling. Only after providing written informed consent for the procedure will the patient's be screened for eligibility for our study. If the patient is eligible, she will be asked by a member of the research team if she is interested in participating. If she is, the study will be explained to her and written consent will be obtained after she is given the opportunity to have all of her questions answered. The patient will then complete a written questionnaire to collect demographic data.

This prospective randomized control trial will consist of two study arms. Participants will be randomly assigned to Arm 1, where a paracervical block will be administered with 20 cc of 1% lidocaine, which is our standard office protocol, or to Arm 2, where a paracervical block will be administered with 20 cc of 1% lidocaine buffered with 8.4% sodium bicarbonate. Prior to the start of the study, study assignments will be generated in a 1:1 ratio.

All patients who consent to the study will receive standard counseling prior to their procedure. The procedure will start with a bimanual exam by the provider. Next, the provider will place a speculum, cleanse the cervix with betadine solution, and place a single-tooth tenaculum on the anterior lip of the cervix. At this point, participants assigned to Arm 1 will receive a paracervical block loaded with 20 cc of 1% lidocaine and injected at 2, 4, 8 and 10 o'clock positions of the cervicovaginal junction. Participants assigned to Arm 2 will receive a paracervical block loaded with 18 cc of 1% lidocaine and 2 cc of 8.4% sodium bicarbonate and inject the block in the same fashion. The research assistant will ask the patient to verbally report their level of pain based on the 100 mm visual analog scale (VAS) at the following points of the procedure:

1. Prior to the start of the procedure (baseline anxiety)
2. After speculum placement
3. After paracervical block
4. After cervical dilation
5. After suction curettage
6. At end of procedure

Inclusion Criteria:

• Pregnant women 14 years and older
• Desiring uterine aspiration for pregnancy or surgical management of a miscarriage
• Gestational age up to 13 weeks and 6 days to be established by best dating (i.e. last menstrual period or earliest ultrasound)
• Treatment plan involves outpatient uterine aspiration
• Participant able to provide informed consent in English and willing to participate in the study

Exclusion Criteria:

• Unable to read, speak, or understand English
• Unable to provide informed consent
• Currently incarcerated
• Under the age of 14 years
• Contraindications to receiving lidocaine or buffered lidocaine

Each patient was assessed for adverse events during their procedure, during their recovery time, and upon discharge from the clinic for an average of one week.

A statistician not involved with the conduct of the study will use a computer random number generator to generate random permuted blocks. This statistician will place allocation assignment cards in sequentially numbered, sealed, opaque envelopes. A different randomization scheme will be used for each location, one at the Kapi'olani office and one at the Queen's office.

A clinic staff member not involved with the conduct of the study will be trained specifically in the opening of the allocation envelopes. The staff member will be trained to open the envelope and remove the study card to read the allocation group: buffered lidocaine or plain lidocaine. The clinic staff member will then prepare the buffered lidocaine or plain lidocaine in an unlabeled syringe, and place it on the surgical tray.